diff --git a/airflow-core/newsfragments/70280.bugfix.rst b/airflow-core/newsfragments/70280.bugfix.rst
new file mode 100644
index 0000000000000..f6f8d8382c8bc
--- /dev/null
+++ b/airflow-core/newsfragments/70280.bugfix.rst
@@ -0,0 +1 @@
+Restored support for ``[core] execute_tasks_new_python_interpreter`` when running tasks with LocalExecutor and CeleryExecutor.
diff --git a/task-sdk/src/airflow/sdk/execution_time/supervisor.py b/task-sdk/src/airflow/sdk/execution_time/supervisor.py
index 87311f02da7a1..27133bc6d4905 100644
--- a/task-sdk/src/airflow/sdk/execution_time/supervisor.py
+++ b/task-sdk/src/airflow/sdk/execution_time/supervisor.py
@@ -515,8 +515,10 @@ def exit(n: int) -> NoReturn:
 
 
 def _should_use_exec() -> bool:
-    """Whether forked children should ``exec`` a fresh interpreter on this platform."""
-    return sys.platform in _FORK_EXEC_PLATFORMS
+    """Whether forked children should ``exec`` a fresh interpreter."""
+    return sys.platform in _FORK_EXEC_PLATFORMS or conf.getboolean(
+        "core", "execute_tasks_new_python_interpreter", fallback=False
+    )
 
 
 def _resolve_child_target(dotted: str) -> Callable[[], None]:
diff --git a/task-sdk/tests/task_sdk/execution_time/test_supervisor.py b/task-sdk/tests/task_sdk/execution_time/test_supervisor.py
index 7ba463567a17a..9bf7c2428f6b9 100644
--- a/task-sdk/tests/task_sdk/execution_time/test_supervisor.py
+++ b/task-sdk/tests/task_sdk/execution_time/test_supervisor.py
@@ -185,6 +185,17 @@
 TI_ID = uuid7()
 
 
+@pytest.mark.parametrize(
+    ("platform", "config_value", "expected"),
+    [("darwin", False, True), ("linux", True, True), ("linux", False, False)],
+)
+def test_should_use_exec_honors_platform_and_config(monkeypatch, platform, config_value, expected):
+    monkeypatch.setattr(supervisor.sys, "platform", platform)
+    monkeypatch.setattr(supervisor.conf, "getboolean", lambda *args, **kwargs: config_value)
+
+    assert supervisor._should_use_exec() is expected
+
+
 def lineno():
     """Returns the current line number in our program."""
     return inspect.currentframe().f_back.f_lineno