diff --git a/src/execution/getVariableSignature.ts b/src/execution/getVariableSignature.ts
index d23c310eb5..8f9fd4a5d2 100644
--- a/src/execution/getVariableSignature.ts
+++ b/src/execution/getVariableSignature.ts
@@ -4,9 +4,12 @@ import type { VariableDefinitionNode } from '../language/ast.js';
 import { print } from '../language/printer.js';
 
 import { isInputType } from '../type/definition.js';
-import type { GraphQLInputType, GraphQLSchema } from '../type/index.js';
+import type {
+  GraphQLDefaultValueUsage,
+  GraphQLInputType,
+  GraphQLSchema,
+} from '../type/index.js';
 
-import { coerceInputLiteral } from '../utilities/coerceInputValue.js';
 import { typeFromAST } from '../utilities/typeFromAST.js';
 
 /**
@@ -18,7 +21,7 @@ import { typeFromAST } from '../utilities/typeFromAST.js';
 export interface GraphQLVariableSignature {
   name: string;
   type: GraphQLInputType;
-  defaultValue: unknown;
+  defaultValue: GraphQLDefaultValueUsage | undefined;
 }
 
 export function getVariableSignature(
@@ -43,8 +46,6 @@ export function getVariableSignature(
   return {
     name: varName,
     type: varType,
-    defaultValue: defaultValue
-      ? coerceInputLiteral(varDefNode.defaultValue, varType)
-      : undefined,
+    defaultValue: defaultValue ? { literal: defaultValue } : undefined,
   };
 }
diff --git a/src/execution/values.ts b/src/execution/values.ts
index c153a616a5..5ac0c7656c 100644
--- a/src/execution/values.ts
+++ b/src/execution/values.ts
@@ -20,6 +20,7 @@ import type { GraphQLDirective } from '../type/directives.js';
 import type { GraphQLSchema } from '../type/schema.js';
 
 import {
+  coerceDefaultValue,
   coerceInputLiteral,
   coerceInputValue,
 } from '../utilities/coerceInputValue.js';
@@ -90,8 +91,11 @@ function coerceVariableValues(
 
     const { name: varName, type: varType } = varSignature;
     if (!Object.hasOwn(inputs, varName)) {
-      if (varDefNode.defaultValue) {
-        coercedValues[varName] = varSignature.defaultValue;
+      if (varSignature.defaultValue) {
+        coercedValues[varName] = coerceDefaultValue(
+          varSignature.defaultValue,
+          varType,
+        );
       } else if (isNonNullType(varType)) {
         const varTypeStr = inspect(varType);
         onError(
@@ -173,8 +177,11 @@ export function experimentalGetArgumentValues(
     const argumentNode = argNodeMap.get(name);
 
     if (argumentNode == null) {
-      if (argDef.defaultValue !== undefined) {
-        coercedValues[name] = argDef.defaultValue;
+      if (argDef.defaultValue) {
+        coercedValues[name] = coerceDefaultValue(
+          argDef.defaultValue,
+          argDef.type,
+        );
       } else if (isNonNullType(argType)) {
         throw new GraphQLError(
           `Argument "${name}" of required type "${inspect(argType)}" ` +
@@ -197,8 +204,11 @@ export function experimentalGetArgumentValues(
         scopedVariableValues == null ||
         !Object.hasOwn(scopedVariableValues, variableName)
       ) {
-        if (argDef.defaultValue !== undefined) {
-          coercedValues[name] = argDef.defaultValue;
+        if (argDef.defaultValue) {
+          coercedValues[name] = coerceDefaultValue(
+            argDef.defaultValue,
+            argDef.type,
+          );
         } else if (isNonNullType(argType)) {
           throw new GraphQLError(
             `Argument "${name}" of required type "${inspect(argType)}" ` +
diff --git a/src/index.ts b/src/index.ts
index ca1fb0430f..b3a6b85902 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -199,6 +199,7 @@ export type {
   GraphQLScalarSerializer,
   GraphQLScalarValueParser,
   GraphQLScalarLiteralParser,
+  GraphQLDefaultValueUsage,
 } from './type/index.js';
 
 // Parse and operate on GraphQL language source files.
diff --git a/src/type/__tests__/definition-test.ts b/src/type/__tests__/definition-test.ts
index 9a491fc31f..c5e6ebf38a 100644
--- a/src/type/__tests__/definition-test.ts
+++ b/src/type/__tests__/definition-test.ts
@@ -4,6 +4,7 @@ import { describe, it } from 'mocha';
 import { identityFunc } from '../../jsutils/identityFunc.js';
 import { inspect } from '../../jsutils/inspect.js';
 
+import { Kind } from '../../language/kinds.js';
 import { parseValue } from '../../language/parser.js';
 
 import type { GraphQLNullableType, GraphQLType } from '../definition.js';
@@ -581,6 +582,63 @@ describe('Type System: Input Objects', () => {
       'not used anymore',
     );
   });
+
+  describe('Input Object fields may have default values', () => {
+    it('accepts an Input Object type with a default value', () => {
+      const inputObjType = new GraphQLInputObjectType({
+        name: 'SomeInputObject',
+        fields: {
+          f: { type: ScalarType, defaultValue: 3 },
+        },
+      });
+      expect(inputObjType.getFields().f).to.deep.include({
+        name: 'f',
+        description: undefined,
+        type: ScalarType,
+        defaultValue: { value: 3 },
+        deprecationReason: undefined,
+        extensions: {},
+        astNode: undefined,
+      });
+    });
+
+    it('accepts an Input Object type with a default value literal', () => {
+      const inputObjType = new GraphQLInputObjectType({
+        name: 'SomeInputObject',
+        fields: {
+          f: {
+            type: ScalarType,
+            defaultValueLiteral: { kind: Kind.INT, value: '3' },
+          },
+        },
+      });
+      expect(inputObjType.getFields().f).to.deep.include({
+        name: 'f',
+        description: undefined,
+        type: ScalarType,
+        defaultValue: { literal: { kind: 'IntValue', value: '3' } },
+        deprecationReason: undefined,
+        extensions: {},
+        astNode: undefined,
+      });
+    });
+
+    it('rejects an Input Object type with potentially conflicting default values', () => {
+      const inputObjType = new GraphQLInputObjectType({
+        name: 'SomeInputObject',
+        fields: {
+          f: {
+            type: ScalarType,
+            defaultValue: 3,
+            defaultValueLiteral: { kind: Kind.INT, value: '3' },
+          },
+        },
+      });
+      expect(() => inputObjType.getFields()).to.throw(
+        'Argument "f" has both a defaultValue and a defaultValueLiteral property, but only one must be provided.',
+      );
+    });
+  });
 });
 
 describe('Type System: List', () => {
diff --git a/src/type/__tests__/predicate-test.ts b/src/type/__tests__/predicate-test.ts
index c1e1fb3059..a71ce8c012 100644
--- a/src/type/__tests__/predicate-test.ts
+++ b/src/type/__tests__/predicate-test.ts
@@ -574,7 +574,10 @@ describe('Type predicates', () => {
         name: 'someArg',
         type: config.type,
         description: undefined,
-        defaultValue: config.defaultValue,
+        defaultValue:
+          config.defaultValue !== undefined
+            ? { value: config.defaultValue }
+            : undefined,
         deprecationReason: null,
         extensions: Object.create(null),
         astNode: undefined,
@@ -622,7 +625,10 @@ describe('Type predicates', () => {
         name: 'someInputField',
         type: config.type,
         description: undefined,
-        defaultValue: config.defaultValue,
+        defaultValue:
+          config.defaultValue !== undefined
+            ? { value: config.defaultValue }
+            : undefined,
         deprecationReason: null,
         extensions: Object.create(null),
         astNode: undefined,
diff --git a/src/type/definition.ts b/src/type/definition.ts
index b0e783b691..9318eb3d41 100644
--- a/src/type/definition.ts
+++ b/src/type/definition.ts
@@ -16,6 +16,7 @@ import { toObjMap } from '../jsutils/toObjMap.js';
 import { GraphQLError } from '../error/GraphQLError.js';
 
 import type {
+  ConstValueNode,
   EnumTypeDefinitionNode,
   EnumTypeExtensionNode,
   EnumValueDefinitionNode,
@@ -799,7 +800,7 @@ export function defineArguments(
     name: assertName(argName),
     description: argConfig.description,
     type: argConfig.type,
-    defaultValue: argConfig.defaultValue,
+    defaultValue: defineDefaultValue(argName, argConfig),
     deprecationReason: argConfig.deprecationReason,
     extensions: toObjMap(argConfig.extensions),
     astNode: argConfig.astNode,
@@ -946,6 +947,7 @@ export interface GraphQLArgumentConfig {
   description?: Maybe<string>;
   type: GraphQLInputType;
   defaultValue?: unknown;
+  defaultValueLiteral?: ConstValueNode | undefined;
   deprecationReason?: Maybe<string>;
   extensions?: Maybe<Readonly<GraphQLArgumentExtensions>>;
   astNode?: Maybe<InputValueDefinitionNode>;
@@ -971,7 +973,7 @@ export interface GraphQLArgument {
   name: string;
   description: Maybe<string>;
   type: GraphQLInputType;
-  defaultValue: unknown;
+  defaultValue: GraphQLDefaultValueUsage | undefined;
   deprecationReason: Maybe<string>;
   extensions: Readonly<GraphQLArgumentExtensions>;
   astNode: Maybe<InputValueDefinitionNode>;
@@ -985,6 +987,26 @@ export type GraphQLFieldMap<TSource, TContext> = ObjMap<
   GraphQLField<TSource, TContext>
 >;
 
+export type GraphQLDefaultValueUsage =
+  | { value: unknown; literal?: never }
+  | { literal: ConstValueNode; value?: never };
+
+export function defineDefaultValue(
+  argName: string,
+  config: GraphQLArgumentConfig | GraphQLInputFieldConfig,
+): GraphQLDefaultValueUsage | undefined {
+  if (config.defaultValue === undefined && !config.defaultValueLiteral) {
+    return;
+  }
+  devAssert(
+    !(config.defaultValue !== undefined && config.defaultValueLiteral),
+    `Argument "${argName}" has both a defaultValue and a defaultValueLiteral property, but only one must be provided.`,
+  );
+  return config.defaultValueLiteral
+    ? { literal: config.defaultValueLiteral }
+    : { value: config.defaultValue };
+}
+
 /**
  * Custom extensions
  *
@@ -1572,7 +1594,7 @@ function defineInputFieldMap(
     name: assertName(fieldName),
     description: fieldConfig.description,
     type: fieldConfig.type,
-    defaultValue: fieldConfig.defaultValue,
+    defaultValue: defineDefaultValue(fieldName, fieldConfig),
     deprecationReason: fieldConfig.deprecationReason,
     extensions: toObjMap(fieldConfig.extensions),
     astNode: fieldConfig.astNode,
@@ -1613,6 +1635,7 @@ export interface GraphQLInputFieldConfig {
   description?: Maybe<string>;
   type: GraphQLInputType;
   defaultValue?: unknown;
+  defaultValueLiteral?: ConstValueNode | undefined;
   deprecationReason?: Maybe<string>;
   extensions?: Maybe<Readonly<GraphQLInputFieldExtensions>>;
   astNode?: Maybe<InputValueDefinitionNode>;
@@ -1624,7 +1647,7 @@ export interface GraphQLInputField {
   name: string;
   description: Maybe<string>;
   type: GraphQLInputType;
-  defaultValue: unknown;
+  defaultValue: GraphQLDefaultValueUsage | undefined;
   deprecationReason: Maybe<string>;
   extensions: Readonly<GraphQLInputFieldExtensions>;
   astNode: Maybe<InputValueDefinitionNode>;
diff --git a/src/type/index.ts b/src/type/index.ts
index 6617a7bfe1..dfbca75ad0 100644
--- a/src/type/index.ts
+++ b/src/type/index.ts
@@ -119,6 +119,7 @@ export type {
   GraphQLScalarSerializer,
   GraphQLScalarValueParser,
   GraphQLScalarLiteralParser,
+  GraphQLDefaultValueUsage,
 } from './definition.js';
 
 export {
diff --git a/src/type/introspection.ts b/src/type/introspection.ts
index e6e121e1cc..b72b162cbb 100644
--- a/src/type/introspection.ts
+++ b/src/type/introspection.ts
@@ -407,8 +407,13 @@ export const __InputValue: GraphQLObjectType = new GraphQLObjectType({
           'A GraphQL-formatted string representing the default value for this input value.',
         resolve(inputValue) {
           const { type, defaultValue } = inputValue;
-          const valueAST = astFromValue(defaultValue, type);
-          return valueAST ? print(valueAST) : null;
+          if (!defaultValue) {
+            return null;
+          }
+          const literal =
+            defaultValue.literal ?? astFromValue(defaultValue.value, type);
+          invariant(literal != null, 'Invalid default value');
+          return print(literal);
         },
       },
       isDeprecated: {
diff --git a/src/utilities/TypeInfo.ts b/src/utilities/TypeInfo.ts
index 75a4eab9ff..e49733f0c2 100644
--- a/src/utilities/TypeInfo.ts
+++ b/src/utilities/TypeInfo.ts
@@ -14,6 +14,7 @@ import { getEnterLeaveForKind } from '../language/visitor.js';
 import type {
   GraphQLArgument,
   GraphQLCompositeType,
+  GraphQLDefaultValueUsage,
   GraphQLEnumValue,
   GraphQLField,
   GraphQLInputField,
@@ -53,7 +54,7 @@ export class TypeInfo {
   private _parentTypeStack: Array<Maybe<GraphQLCompositeType>>;
   private _inputTypeStack: Array<Maybe<GraphQLInputType>>;
   private _fieldDefStack: Array<Maybe<GraphQLField<unknown, unknown>>>;
-  private _defaultValueStack: Array<Maybe<unknown>>;
+  private _defaultValueStack: Array<GraphQLDefaultValueUsage | undefined>;
   private _directive: Maybe<GraphQLDirective>;
   private _argument: Maybe<GraphQLArgument>;
   private _enumValue: Maybe<GraphQLEnumValue>;
@@ -124,7 +125,7 @@ export class TypeInfo {
     return this._fieldDefStack.at(-1);
   }
 
-  getDefaultValue(): Maybe<unknown> {
+  getDefaultValue(): GraphQLDefaultValueUsage | undefined {
     return this._defaultValueStack.at(-1);
   }
 
diff --git a/src/utilities/__tests__/buildClientSchema-test.ts b/src/utilities/__tests__/buildClientSchema-test.ts
index b6b433626d..0ad292d03a 100644
--- a/src/utilities/__tests__/buildClientSchema-test.ts
+++ b/src/utilities/__tests__/buildClientSchema-test.ts
@@ -439,6 +439,7 @@ describe('Type System: build schema from introspection', () => {
       }
 
       type Query {
+        defaultID(intArg: ID = "123"): String
         defaultInt(intArg: Int = 30): String
         defaultList(listArg: [Int] = [1, 2, 3]): String
         defaultObject(objArg: Geo = { lat: 37.485, lon: -122.148 }): String
@@ -609,6 +610,28 @@ describe('Type System: build schema from introspection', () => {
     expect(result.data).to.deep.equal({ foo: 'bar' });
   });
 
+  it('can use client schema for execution if resolvers are added', () => {
+    const schema = buildSchema(`
+      type Query {
+        foo(bar: String = "abc"): String
+      }
+    `);
+
+    const introspection = introspectionFromSchema(schema);
+    const clientSchema = buildClientSchema(introspection);
+
+    const QueryType: GraphQLObjectType = clientSchema.getType('Query') as any;
+    QueryType.getFields().foo.resolve = (_value, args) => args.bar;
+
+    const result = graphqlSync({
+      schema: clientSchema,
+      source: '{ foo }',
+    });
+
+    expect(result.data).to.deep.equal({ foo: 'abc' });
+    expect(result.data).to.deep.equal({ foo: 'abc' });
+  });
+
   it('can build invalid schema', () => {
     const schema = buildSchema('type Query', { assumeValid: true });
 
diff --git a/src/utilities/__tests__/coerceInputValue-test.ts b/src/utilities/__tests__/coerceInputValue-test.ts
index 15467e8456..78dede7b81 100644
--- a/src/utilities/__tests__/coerceInputValue-test.ts
+++ b/src/utilities/__tests__/coerceInputValue-test.ts
@@ -5,6 +5,7 @@ import { identityFunc } from '../../jsutils/identityFunc.js';
 import { invariant } from '../../jsutils/invariant.js';
 import type { ObjMap } from '../../jsutils/ObjMap.js';
 
+import { Kind } from '../../language/kinds.js';
 import { parseValue } from '../../language/parser.js';
 import { print } from '../../language/printer.js';
 
@@ -24,7 +25,11 @@ import {
   GraphQLString,
 } from '../../type/scalars.js';
 
-import { coerceInputLiteral, coerceInputValue } from '../coerceInputValue.js';
+import {
+  coerceDefaultValue,
+  coerceInputLiteral,
+  coerceInputValue,
+} from '../coerceInputValue.js';
 
 interface CoerceResult {
   value: unknown;
@@ -716,10 +721,14 @@ describe('coerceInputLiteral', () => {
       name: 'TestInput',
       fields: {
         int: { type: GraphQLInt, defaultValue: 42 },
+        float: {
+          type: GraphQLFloat,
+          defaultValueLiteral: { kind: Kind.FLOAT, value: '3.14' },
+        },
       },
     });
 
-    test('{}', type, { int: 42 });
+    test('{}', type, { int: 42, float: 3.14 });
   });
 
   const testInputObj = new GraphQLInputObjectType({
@@ -807,3 +816,26 @@ describe('coerceInputLiteral', () => {
     });
   });
 });
+
+describe('coerceDefaultValue', () => {
+  it('memoizes coercion', () => {
+    const parseValueCalls: any = [];
+
+    const spyScalar = new GraphQLScalarType({
+      name: 'SpyScalar',
+      parseValue(value) {
+        parseValueCalls.push(value);
+        return value;
+      },
+    });
+
+    const defaultValueUsage = {
+      literal: { kind: Kind.STRING, value: 'hello' },
+    } as const;
+    expect(coerceDefaultValue(defaultValueUsage, spyScalar)).to.equal('hello');
+
+    // Call a second time
+    expect(coerceDefaultValue(defaultValueUsage, spyScalar)).to.equal('hello');
+    expect(parseValueCalls).to.deep.equal(['hello']);
+  });
+});
diff --git a/src/utilities/buildClientSchema.ts b/src/utilities/buildClientSchema.ts
index c109b18fa7..f1f52e8a52 100644
--- a/src/utilities/buildClientSchema.ts
+++ b/src/utilities/buildClientSchema.ts
@@ -32,7 +32,6 @@ import { specifiedScalarTypes } from '../type/scalars.js';
 import type { GraphQLSchemaValidationOptions } from '../type/schema.js';
 import { GraphQLSchema } from '../type/schema.js';
 
-import { coerceInputLiteral } from './coerceInputValue.js';
 import type {
   IntrospectionDirective,
   IntrospectionEnumType,
@@ -374,17 +373,13 @@ export function buildClientSchema(
       );
     }
 
-    const defaultValue =
-      inputValueIntrospection.defaultValue != null
-        ? coerceInputLiteral(
-            parseConstValue(inputValueIntrospection.defaultValue),
-            type,
-          )
-        : undefined;
     return {
       description: inputValueIntrospection.description,
       type,
-      defaultValue,
+      defaultValueLiteral:
+        inputValueIntrospection.defaultValue != null
+          ? parseConstValue(inputValueIntrospection.defaultValue)
+          : undefined,
       deprecationReason: inputValueIntrospection.deprecationReason,
     };
   }
diff --git a/src/utilities/coerceInputValue.ts b/src/utilities/coerceInputValue.ts
index 37ac966aab..7fbce75fb5 100644
--- a/src/utilities/coerceInputValue.ts
+++ b/src/utilities/coerceInputValue.ts
@@ -15,7 +15,10 @@ import { GraphQLError } from '../error/GraphQLError.js';
 import type { ValueNode, VariableNode } from '../language/ast.js';
 import { Kind } from '../language/kinds.js';
 
-import type { GraphQLInputType } from '../type/definition.js';
+import type {
+  GraphQLDefaultValueUsage,
+  GraphQLInputType,
+} from '../type/definition.js';
 import {
   assertLeafType,
   isInputObjectType,
@@ -111,8 +114,11 @@ function coerceInputValueImpl(
       const fieldValue = inputValue[field.name];
 
       if (fieldValue === undefined) {
-        if (field.defaultValue !== undefined) {
-          coercedValue[field.name] = field.defaultValue;
+        if (field.defaultValue) {
+          coercedValue[field.name] = coerceDefaultValue(
+            field.defaultValue,
+            field.type,
+          );
         } else if (isNonNullType(field.type)) {
           const typeStr = inspect(field.type);
           onError(
@@ -322,8 +328,11 @@ export function coerceInputLiteral(
         if (isRequiredInputField(field)) {
           return; // Invalid: intentionally return no value.
         }
-        if (field.defaultValue !== undefined) {
-          coercedValue[field.name] = field.defaultValue;
+        if (field.defaultValue) {
+          coercedValue[field.name] = coerceDefaultValue(
+            field.defaultValue,
+            field.type,
+          );
         }
       } else {
         const fieldValue = coerceInputLiteral(
@@ -375,3 +384,21 @@ function getVariableValue(
 
   return variables?.[varName];
 }
+
+/**
+ * @internal
+ */
+export function coerceDefaultValue(
+  defaultValue: GraphQLDefaultValueUsage,
+  type: GraphQLInputType,
+): unknown {
+  // Memoize the result of coercing the default value in a hidden field.
+  let coercedValue = (defaultValue as any)._memoizedCoercedValue;
+  if (coercedValue === undefined) {
+    coercedValue = defaultValue.literal
+      ? coerceInputLiteral(defaultValue.literal, type)
+      : defaultValue.value;
+    (defaultValue as any)._memoizedCoercedValue = coercedValue;
+  }
+  return coercedValue;
+}
diff --git a/src/utilities/extendSchema.ts b/src/utilities/extendSchema.ts
index d18b53d028..f43c15330d 100644
--- a/src/utilities/extendSchema.ts
+++ b/src/utilities/extendSchema.ts
@@ -83,8 +83,6 @@ import { assertValidSDLExtension } from '../validation/validate.js';
 
 import { getDirectiveValues } from '../execution/values.js';
 
-import { coerceInputLiteral } from './coerceInputValue.js';
-
 interface Options extends GraphQLSchemaValidationOptions {
   /**
    * Set to true to assume the SDL is valid.
@@ -535,9 +533,7 @@ export function extendSchemaImpl(
       argConfigMap[arg.name.value] = {
         type,
         description: arg.description?.value,
-        defaultValue: arg.defaultValue
-          ? coerceInputLiteral(arg.defaultValue, type)
-          : undefined,
+        defaultValueLiteral: arg.defaultValue,
         deprecationReason: getDeprecationReason(arg),
         astNode: arg,
       };
@@ -564,9 +560,7 @@ export function extendSchemaImpl(
         inputFieldMap[field.name.value] = {
           type,
           description: field.description?.value,
-          defaultValue: field.defaultValue
-            ? coerceInputLiteral(field.defaultValue, type)
-            : undefined,
+          defaultValueLiteral: field.defaultValue,
           deprecationReason: getDeprecationReason(field),
           astNode: field,
         };
diff --git a/src/utilities/findBreakingChanges.ts b/src/utilities/findBreakingChanges.ts
index 2921074625..e6f4f79055 100644
--- a/src/utilities/findBreakingChanges.ts
+++ b/src/utilities/findBreakingChanges.ts
@@ -5,6 +5,7 @@ import { keyMap } from '../jsutils/keyMap.js';
 import { print } from '../language/printer.js';
 
 import type {
+  GraphQLDefaultValueUsage,
   GraphQLEnumType,
   GraphQLField,
   GraphQLInputObjectType,
@@ -534,8 +535,11 @@ function typeKindName(type: GraphQLNamedType): string {
   invariant(false, 'Unexpected type: ' + inspect(type));
 }
 
-function stringifyValue(value: unknown, type: GraphQLInputType): string {
-  const ast = astFromValue(value, type);
+function stringifyValue(
+  defaultValue: GraphQLDefaultValueUsage,
+  type: GraphQLInputType,
+): string {
+  const ast = defaultValue.literal ?? astFromValue(defaultValue.value, type);
   invariant(ast != null);
   return print(sortValueNode(ast));
 }
diff --git a/src/utilities/printSchema.ts b/src/utilities/printSchema.ts
index 7d4a5e4f5a..b02580c6fa 100644
--- a/src/utilities/printSchema.ts
+++ b/src/utilities/printSchema.ts
@@ -259,10 +259,13 @@ function printArgs(
 }
 
 function printInputValue(arg: GraphQLInputField): string {
-  const defaultAST = astFromValue(arg.defaultValue, arg.type);
   let argDecl = arg.name + ': ' + String(arg.type);
-  if (defaultAST) {
-    argDecl += ` = ${print(defaultAST)}`;
+  if (arg.defaultValue) {
+    const literal =
+      arg.defaultValue.literal ??
+      astFromValue(arg.defaultValue.value, arg.type);
+    invariant(literal != null, 'Invalid default value');
+    argDecl += ` = ${print(literal)}`;
   }
   return argDecl + printDeprecated(arg.deprecationReason);
 }
diff --git a/src/utilities/valueFromAST.ts b/src/utilities/valueFromAST.ts
index eb95ea3cdb..5b1ced4302 100644
--- a/src/utilities/valueFromAST.ts
+++ b/src/utilities/valueFromAST.ts
@@ -14,6 +14,8 @@ import {
   isNonNullType,
 } from '../type/definition.js';
 
+import { coerceDefaultValue } from './coerceInputValue.js';
+
 /**
  * Produces a JavaScript value given a GraphQL Value AST.
  *
@@ -114,8 +116,11 @@ export function valueFromAST(
     for (const field of Object.values(type.getFields())) {
       const fieldNode = fieldNodes.get(field.name);
       if (fieldNode == null || isMissingVariable(fieldNode.value, variables)) {
-        if (field.defaultValue !== undefined) {
-          coercedObj[field.name] = field.defaultValue;
+        if (field.defaultValue) {
+          coercedObj[field.name] = coerceDefaultValue(
+            field.defaultValue,
+            field.type,
+          );
         } else if (isNonNullType(field.type)) {
           return; // Invalid: intentionally return no value.
         }
diff --git a/src/validation/ValidationContext.ts b/src/validation/ValidationContext.ts
index 7f7114c4ef..d45e7a46a4 100644
--- a/src/validation/ValidationContext.ts
+++ b/src/validation/ValidationContext.ts
@@ -19,6 +19,7 @@ import { visit } from '../language/visitor.js';
 import type {
   GraphQLArgument,
   GraphQLCompositeType,
+  GraphQLDefaultValueUsage,
   GraphQLEnumValue,
   GraphQLField,
   GraphQLInputType,
@@ -34,7 +35,7 @@ type NodeWithSelectionSet = OperationDefinitionNode | FragmentDefinitionNode;
 interface VariableUsage {
   readonly node: VariableNode;
   readonly type: Maybe<GraphQLInputType>;
-  readonly defaultValue: Maybe<unknown>;
+  readonly defaultValue: GraphQLDefaultValueUsage | undefined;
   readonly fragmentVariableDefinition: Maybe<VariableDefinitionNode>;
 }
 
diff --git a/src/validation/rules/VariablesInAllowedPositionRule.ts b/src/validation/rules/VariablesInAllowedPositionRule.ts
index e68a595c4f..888e49d3dd 100644
--- a/src/validation/rules/VariablesInAllowedPositionRule.ts
+++ b/src/validation/rules/VariablesInAllowedPositionRule.ts
@@ -7,7 +7,10 @@ import type { ValueNode, VariableDefinitionNode } from '../../language/ast.js';
 import { Kind } from '../../language/kinds.js';
 import type { ASTVisitor } from '../../language/visitor.js';
 
-import type { GraphQLType } from '../../type/definition.js';
+import type {
+  GraphQLDefaultValueUsage,
+  GraphQLType,
+} from '../../type/definition.js';
 import { isNonNullType } from '../../type/definition.js';
 import type { GraphQLSchema } from '../../type/schema.js';
 
@@ -95,7 +98,7 @@ function allowedVariableUsage(
   varType: GraphQLType,
   varDefaultValue: Maybe<ValueNode>,
   locationType: GraphQLType,
-  locationDefaultValue: Maybe<unknown>,
+  locationDefaultValue: GraphQLDefaultValueUsage | undefined,
 ): boolean {
   if (isNonNullType(locationType) && !isNonNullType(varType)) {
     const hasNonNullVariableDefaultValue =