diff --git a/homeassistant/core.py b/homeassistant/core.py
index 9c5d32934a8..d7535907dfc 100644
--- a/homeassistant/core.py
+++ b/homeassistant/core.py
@@ -72,6 +72,7 @@ from .const import (
     MAX_EXPECTED_ENTITY_IDS,
     MAX_LENGTH_EVENT_EVENT_TYPE,
     MAX_LENGTH_STATE_STATE,
+    STATE_UNKNOWN,
     __version__,
 )
 from .exceptions import (
@@ -1794,18 +1795,13 @@ class State:
     ) -> None:
         """Initialize a new state."""
         self._cache: dict[str, Any] = {}
-        state = str(state)
-
         if validate_entity_id and not valid_entity_id(entity_id):
             raise InvalidEntityFormatError(
                 f"Invalid entity id encountered: {entity_id}. "
                 "Format should be <domain>.<object_id>"
             )
-
-        validate_state(state)
-
         self.entity_id = entity_id
-        self.state = state
+        self.state = state if type(state) is str else str(state)
         # State only creates and expects a ReadOnlyDict so
         # there is no need to check for subclassing with
         # isinstance here so we can use the faster type check.
@@ -2270,9 +2266,11 @@ class StateMachine:
 
         This method must be run in the event loop.
         """
+        state = str(new_state)
+        validate_state(state)
         self.async_set_internal(
             entity_id.lower(),
-            str(new_state),
+            state,
             attributes or {},
             force_update,
             context,
@@ -2298,6 +2296,8 @@ class StateMachine:
         breaking changes to this function in the future and it
         should not be used in integrations.
 
+        Callers are responsible for ensuring the entity_id is lower case.
+
         This method must be run in the event loop.
         """
         # Most cases the key will be in the dict
@@ -2356,6 +2356,16 @@ class StateMachine:
                 assert old_state is not None
             attributes = old_state.attributes
 
+        if not same_state and len(new_state) > MAX_LENGTH_STATE_STATE:
+            _LOGGER.error(
+                "State %s for %s is longer than %s, falling back to %s",
+                new_state,
+                entity_id,
+                MAX_LENGTH_STATE_STATE,
+                STATE_UNKNOWN,
+            )
+            new_state = STATE_UNKNOWN
+
         # This is intentionally called with positional only arguments for performance
         # reasons
         state = State(
diff --git a/homeassistant/helpers/entity.py b/homeassistant/helpers/entity.py
index 52aac7cca79..a3edf6bb64f 100644
--- a/homeassistant/helpers/entity.py
+++ b/homeassistant/helpers/entity.py
@@ -31,7 +31,6 @@ from homeassistant.const import (
     ATTR_SUPPORTED_FEATURES,
     ATTR_UNIT_OF_MEASUREMENT,
     DEVICE_DEFAULT_NAME,
-    MAX_LENGTH_STATE_STATE,
     STATE_OFF,
     STATE_ON,
     STATE_UNAVAILABLE,
@@ -1217,16 +1216,6 @@ class Entity(
             self._context = None
             self._context_set = None
 
-        if len(state) > MAX_LENGTH_STATE_STATE:
-            _LOGGER.error(
-                "State %s for %s is longer than %s, falling back to %s",
-                state,
-                self.entity_id,
-                MAX_LENGTH_STATE_STATE,
-                STATE_UNKNOWN,
-            )
-            state = STATE_UNKNOWN
-
         # Intentionally called with positional args for performance reasons
         self.hass.states.async_set_internal(
             self.entity_id,
diff --git a/tests/helpers/test_entity.py b/tests/helpers/test_entity.py
index 04159a91d6b..137b2a7e8a7 100644
--- a/tests/helpers/test_entity.py
+++ b/tests/helpers/test_entity.py
@@ -1711,7 +1711,7 @@ async def test_invalid_state(
     ent.async_write_ha_state()
     assert hass.states.get("test.test").state == STATE_UNKNOWN
     assert (
-        "homeassistant.helpers.entity",
+        "homeassistant.core",
         logging.ERROR,
         f"State {long_state} for test.test is longer than 255, "
         f"falling back to {STATE_UNKNOWN}",
diff --git a/tests/test_core.py b/tests/test_core.py
index ceab3ce327c..50f7f92727b 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -35,6 +35,7 @@ from homeassistant.const import (
     EVENT_STATE_CHANGED,
     EVENT_STATE_REPORTED,
     MATCH_ALL,
+    STATE_UNKNOWN,
 )
 from homeassistant.core import (
     CoreState,
@@ -1368,9 +1369,6 @@ def test_state_init() -> None:
     with pytest.raises(InvalidEntityFormatError):
         ha.State("invalid_entity_format", "test_state")
 
-    with pytest.raises(InvalidStateError):
-        ha.State("domain.long_state", "t" * 256)
-
 
 def test_state_domain() -> None:
     """Test domain."""
@@ -1440,6 +1438,38 @@ def test_state_repr() -> None:
     )
 
 
+async def test_statemachine_async_set_invalid_state(hass: HomeAssistant) -> None:
+    """Test setting an invalid state with the async_set method."""
+    with pytest.raises(
+        InvalidStateError,
+        match="Invalid state with length 256. State max length is 255 characters.",
+    ):
+        hass.states.async_set("light.bowl", "o" * 256, {})
+
+
+async def test_statemachine_async_set_internal_invalid_state(
+    hass: HomeAssistant, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Test setting an invalid state with the async_set_internal method."""
+    long_state = "o" * 256
+    hass.states.async_set_internal(
+        "light.bowl",
+        long_state,
+        {},
+        force_update=False,
+        context=None,
+        state_info=None,
+        timestamp=time.time(),
+    )
+    assert hass.states.get("light.bowl").state == STATE_UNKNOWN
+    assert (
+        "homeassistant.core",
+        logging.ERROR,
+        f"State {long_state} for light.bowl is longer than 255, "
+        f"falling back to {STATE_UNKNOWN}",
+    ) in caplog.record_tuples
+
+
 async def test_statemachine_is_state(hass: HomeAssistant) -> None:
     """Test is_state method."""
     hass.states.async_set("light.bowl", "on", {})