diff --git a/composer/loggers/mlflow_logger.py b/composer/loggers/mlflow_logger.py
index 9ed6415dce..dcbed33d96 100644
--- a/composer/loggers/mlflow_logger.py
+++ b/composer/loggers/mlflow_logger.py
@@ -148,7 +148,7 @@ def init(self, state: State, logger: Logger) -> None:
 
         # Store the Composer run name in the MLFlow run tags so it can be retrieved for autoresume.
         self.tags = self.tags or {}
-        self.tags['run_name'] = state.run_name
+        self.tags['run_name'] = os.environ.get('RUN_NAME', state.run_name)
 
         # Adjust name and group based on `rank_zero_only`.
         if not self._rank_zero_only:
@@ -171,16 +171,6 @@ def init(self, state: State, logger: Logger) -> None:
                     output_format='list',
                 )
 
-                # Check for the old tag (`composer_run_name`) For backwards compatibility in case a run using the old
-                # tag fails and the run is resumed with a newer version of Composer that uses `run_name` instead of
-                # `composer_run_name`.
-                if len(existing_runs) == 0:
-                    existing_runs = mlflow.search_runs(
-                        experiment_ids=[self._experiment_id],
-                        filter_string=f'tags.composer_run_name = "{state.run_name}"',
-                        output_format='list',
-                    )
-
                 if len(existing_runs) > 0:
                     self._run_id = existing_runs[0].info.run_id
                 else:
diff --git a/tests/loggers/test_mlflow_logger.py b/tests/loggers/test_mlflow_logger.py
index 22b0445e2d..b97c108633 100644
--- a/tests/loggers/test_mlflow_logger.py
+++ b/tests/loggers/test_mlflow_logger.py
@@ -6,7 +6,7 @@
 import os
 import time
 from pathlib import Path
-from unittest.mock import MagicMock
+from unittest.mock import MagicMock, patch
 
 import numpy as np
 import pytest
@@ -190,24 +190,52 @@ def test_mlflow_experiment_init_existing_composer_run(monkeypatch):
     assert test_logger._run_id == existing_id
 
 
-def test_mlflow_experiment_init_existing_composer_run_with_old_tag(monkeypatch):
-    """ Test that an existing MLFlow run is used if one exists with the old `composer_run_name` tag.
-    """
+@pytest.fixture
+def mock_mlflow_client():
+    with patch('mlflow.tracking.MlflowClient') as MockClient:
+        mock_create_run = MagicMock(return_value=MagicMock(info=MagicMock(run_id='mock-run-id')))
+        MockClient.return_value.create_run = mock_create_run
+        yield MockClient
+
+
+def test_mlflow_logger_uses_env_var_run_name(monkeypatch, mock_mlflow_client):
+    """Test that MLFlowLogger uses the 'RUN_NAME' environment variable if set."""
     mlflow = pytest.importorskip('mlflow')
 
     monkeypatch.setattr(mlflow, 'set_tracking_uri', MagicMock())
     monkeypatch.setattr(mlflow, 'start_run', MagicMock())
 
+    from composer.loggers.mlflow_logger import MLFlowLogger
+    mock_state = MagicMock()
+    mock_state.run_name = 'dummy-run-name'
+    monkeypatch.setenv('RUN_NAME', 'env-run-name')
+
+    test_logger = MLFlowLogger()
+    test_logger.init(state=mock_state, logger=MagicMock())
+
+    assert test_logger.tags is not None
+    assert test_logger.tags['run_name'] == 'env-run-name'
+    monkeypatch.delenv('RUN_NAME')
+
+
+def test_mlflow_logger_uses_state_run_name_if_no_env_var_set(monkeypatch, mock_mlflow_client):
+    """Test that MLFlowLogger uses the state's run name if no 'RUN_NAME' environment variable is set."""
+    mlflow = pytest.importorskip('mlflow')
+
+    monkeypatch.setattr(mlflow, 'set_tracking_uri', MagicMock())
+    monkeypatch.setattr(mlflow, 'start_run', MagicMock())
     mock_state = MagicMock()
-    mock_state.composer_run_name = 'dummy-run-name'
+    mock_state.run_name = 'state-run-name'
 
     existing_id = 'dummy-id'
     mock_search_runs = MagicMock(return_value=[MagicMock(info=MagicMock(run_id=existing_id))])
     monkeypatch.setattr(mlflow, 'search_runs', mock_search_runs)
 
+    from composer.loggers.mlflow_logger import MLFlowLogger
     test_logger = MLFlowLogger()
     test_logger.init(state=mock_state, logger=MagicMock())
-    assert test_logger._run_id == existing_id
+    assert test_logger.tags is not None
+    assert test_logger.tags['run_name'] == 'state-run-name'
 
 
 def test_mlflow_experiment_set_up(tmp_path):