diff --git a/litellm/proxy/proxy_server.py b/litellm/proxy/proxy_server.py
index 27132c90e05..5ca5fea9c60 100644
--- a/litellm/proxy/proxy_server.py
+++ b/litellm/proxy/proxy_server.py
@@ -5318,6 +5318,7 @@ class ProxyConfig:
                         # these are litellm callbacks - "langfuse", "sentry", "wandb"
                         else:
                             litellm.logging_callback_manager.add_litellm_success_callback(callback)
+                            _add_custom_logger_callback_to_specific_event(callback, "success")
                             if "prometheus" in callback:
                                 from litellm.integrations.prometheus import (
                                     PrometheusLogger,
@@ -5345,6 +5346,7 @@ class ProxyConfig:
                         # these are litellm callbacks - "langfuse", "sentry", "wandb"
                         else:
                             litellm.logging_callback_manager.add_litellm_failure_callback(callback)
+                            _add_custom_logger_callback_to_specific_event(callback, "failure")
                     print(  # noqa: T201
                         f"{blue_color_code} Initialized Failure Callbacks - {litellm.failure_callback} {reset_color_code}"
                     )
diff --git a/tests/test_litellm/proxy/test_proxy_server.py b/tests/test_litellm/proxy/test_proxy_server.py
index 4ed6a468371..a2c4ae9878a 100644
--- a/tests/test_litellm/proxy/test_proxy_server.py
+++ b/tests/test_litellm/proxy/test_proxy_server.py
@@ -3153,6 +3153,29 @@ async def test_custom_ui_sso_sign_in_handler_config_loading():
         os.unlink(config_file_path)
 
 
+@pytest.mark.asyncio
+async def test_load_config_eagerly_initializes_string_success_callback(tmp_path, monkeypatch):
+    from litellm.integrations.generic_api.generic_api_callback import GenericAPILogger
+    from litellm.proxy.proxy_server import ProxyConfig
+
+    config_file = tmp_path / "config.yaml"
+    config_file.write_text(
+        "model_list: []\n"
+        "litellm_settings:\n"
+        "  success_callback:\n"
+        "    - generic_api\n"
+    )
+    monkeypatch.setenv("GENERIC_LOGGER_ENDPOINT", "http://127.0.0.1:8899/")
+
+    monkeypatch.setattr(litellm, "success_callback", [])
+    monkeypatch.setattr(litellm, "_async_success_callback", [])
+    monkeypatch.setattr(litellm, "failure_callback", [])
+    monkeypatch.setattr(litellm, "_async_failure_callback", [])
+    await ProxyConfig().load_config(router=MagicMock(), config_file_path=str(config_file))
+    assert any(isinstance(callback, GenericAPILogger) for callback in litellm._async_success_callback)
+    assert "generic_api" not in litellm.success_callback
+
+
 @pytest.mark.asyncio
 async def test_load_config_max_budget_env_var_coerced_to_float(tmp_path, monkeypatch):
     """