diff --git a/homeassistant/components/actiontec/device_tracker.py b/homeassistant/components/actiontec/device_tracker.py
index d7e6f5be494..8dc3f095437 100644
--- a/homeassistant/components/actiontec/device_tracker.py
+++ b/homeassistant/components/actiontec/device_tracker.py
@@ -55,7 +55,7 @@ class ActiontecDeviceScanner(DeviceScanner):
         self._update_info()
         return [client.mac_address for client in self.last_results]
 
-    def get_device_name(self, device: str) -> str | None:  # type: ignore[override]
+    def get_device_name(self, device: str) -> str | None:
         """Return the name of the given device or None if we don't know."""
         for client in self.last_results:
             if client.mac_address == device:
diff --git a/homeassistant/components/device_tracker/config_entry.py b/homeassistant/components/device_tracker/config_entry.py
index 9a8c77686a1..6f4e608520c 100644
--- a/homeassistant/components/device_tracker/config_entry.py
+++ b/homeassistant/components/device_tracker/config_entry.py
@@ -82,19 +82,19 @@ class TrackerEntity(BaseTrackerEntity):
         return 0
 
     @property
-    def location_name(self) -> str:
+    def location_name(self) -> str | None:
         """Return a location name for the current location of the device."""
         return None
 
     @property
-    def latitude(self) -> float:
+    def latitude(self) -> float | None:
         """Return latitude value of the device."""
-        return NotImplementedError
+        raise NotImplementedError
 
     @property
-    def longitude(self) -> float:
+    def longitude(self) -> float | None:
         """Return longitude value of the device."""
-        return NotImplementedError
+        raise NotImplementedError
 
     @property
     def state(self):
@@ -102,7 +102,7 @@ class TrackerEntity(BaseTrackerEntity):
         if self.location_name:
             return self.location_name
 
-        if self.latitude is not None:
+        if self.latitude is not None and self.longitude is not None:
             zone_state = zone.async_active_zone(
                 self.hass, self.latitude, self.longitude, self.location_accuracy
             )
diff --git a/homeassistant/components/device_tracker/legacy.py b/homeassistant/components/device_tracker/legacy.py
index e1eb897f1ba..3427bf9595e 100644
--- a/homeassistant/components/device_tracker/legacy.py
+++ b/homeassistant/components/device_tracker/legacy.py
@@ -309,7 +309,7 @@ async def async_create_platform_type(
 def async_setup_scanner_platform(
     hass: HomeAssistant,
     config: ConfigType,
-    scanner: Any,
+    scanner: DeviceScanner,
     async_see_device: Callable,
     platform: str,
 ):
@@ -324,7 +324,7 @@ def async_setup_scanner_platform(
     # Initial scan of each mac we also tell about host name for config
     seen: Any = set()
 
-    async def async_device_tracker_scan(now: dt_util.dt.datetime):
+    async def async_device_tracker_scan(now: dt_util.dt.datetime | None):
         """Handle interval matches."""
         if update_lock.locked():
             LOGGER.warning(
@@ -424,21 +424,21 @@ class DeviceTracker:
 
     def see(
         self,
-        mac: str = None,
-        dev_id: str = None,
-        host_name: str = None,
-        location_name: str = None,
-        gps: GPSType = None,
-        gps_accuracy: int = None,
-        battery: int = None,
-        attributes: dict = None,
+        mac: str | None = None,
+        dev_id: str | None = None,
+        host_name: str | None = None,
+        location_name: str | None = None,
+        gps: GPSType | None = None,
+        gps_accuracy: int | None = None,
+        battery: int | None = None,
+        attributes: dict | None = None,
         source_type: str = SOURCE_TYPE_GPS,
-        picture: str = None,
-        icon: str = None,
-        consider_home: timedelta = None,
+        picture: str | None = None,
+        icon: str | None = None,
+        consider_home: timedelta | None = None,
     ):
         """Notify the device tracker that you see a device."""
-        self.hass.add_job(
+        self.hass.create_task(
             self.async_see(
                 mac,
                 dev_id,
@@ -457,19 +457,19 @@ class DeviceTracker:
 
     async def async_see(
         self,
-        mac: str = None,
-        dev_id: str = None,
-        host_name: str = None,
-        location_name: str = None,
-        gps: GPSType = None,
-        gps_accuracy: int = None,
-        battery: int = None,
-        attributes: dict = None,
+        mac: str | None = None,
+        dev_id: str | None = None,
+        host_name: str | None = None,
+        location_name: str | None = None,
+        gps: GPSType | None = None,
+        gps_accuracy: int | None = None,
+        battery: int | None = None,
+        attributes: dict | None = None,
         source_type: str = SOURCE_TYPE_GPS,
-        picture: str = None,
-        icon: str = None,
-        consider_home: timedelta = None,
-    ):
+        picture: str | None = None,
+        icon: str | None = None,
+        consider_home: timedelta | None = None,
+    ) -> None:
         """Notify the device tracker that you see a device.
 
         This method is a coroutine.
@@ -480,13 +480,13 @@ class DeviceTracker:
         if mac is not None:
             mac = str(mac).upper()
             device = self.mac_to_dev.get(mac)
-            if not device:
+            if device is None:
                 dev_id = util.slugify(host_name or "") or util.slugify(mac)
         else:
             dev_id = cv.slug(str(dev_id).lower())
             device = self.devices.get(dev_id)
 
-        if device:
+        if device is not None:
             await device.async_seen(
                 host_name,
                 location_name,
@@ -501,6 +501,9 @@ class DeviceTracker:
                 device.async_write_ha_state()
             return
 
+        # If it's None then device is not None and we can't get here.
+        assert dev_id is not None
+
         # Guard from calling see on entity registry entities.
         entity_id = f"{DOMAIN}.{dev_id}"
         if registry.async_is_registered(entity_id):
@@ -598,15 +601,13 @@ class DeviceTracker:
 class Device(RestoreEntity):
     """Base class for a tracked device."""
 
-    host_name: str = None
-    location_name: str = None
-    gps: GPSType = None
+    host_name: str | None = None
+    location_name: str | None = None
+    gps: GPSType | None = None
     gps_accuracy: int = 0
-    last_seen: dt_util.dt.datetime = None
-    consider_home: dt_util.dt.timedelta = None
-    battery: int = None
-    attributes: dict = None
-    icon: str = None
+    last_seen: dt_util.dt.datetime | None = None
+    battery: int | None = None
+    attributes: dict | None = None
 
     # Track if the last update of this device was HOME.
     last_update_home = False
@@ -618,11 +619,11 @@ class Device(RestoreEntity):
         consider_home: timedelta,
         track: bool,
         dev_id: str,
-        mac: str,
-        name: str = None,
-        picture: str = None,
-        gravatar: str = None,
-        icon: str = None,
+        mac: str | None,
+        name: str | None = None,
+        picture: str | None = None,
+        gravatar: str | None = None,
+        icon: str | None = None,
     ) -> None:
         """Initialize a device."""
         self.hass = hass
@@ -648,11 +649,11 @@ class Device(RestoreEntity):
         else:
             self.config_picture = picture
 
-        self.icon = icon
+        self._icon = icon
 
-        self.source_type = None
+        self.source_type: str | None = None
 
-        self._attributes = {}
+        self._attributes: dict[str, Any] = {}
 
     @property
     def name(self):
@@ -686,21 +687,26 @@ class Device(RestoreEntity):
         return attributes
 
     @property
-    def extra_state_attributes(self):
+    def extra_state_attributes(self) -> dict[str, Any]:
         """Return device state attributes."""
         return self._attributes
 
+    @property
+    def icon(self) -> str | None:
+        """Return device icon."""
+        return self._icon
+
     async def async_seen(
         self,
-        host_name: str = None,
-        location_name: str = None,
-        gps: GPSType = None,
-        gps_accuracy=0,
-        battery: int = None,
-        attributes: dict = None,
+        host_name: str | None = None,
+        location_name: str | None = None,
+        gps: GPSType | None = None,
+        gps_accuracy: int | None = None,
+        battery: int | None = None,
+        attributes: dict[str, Any] | None = None,
         source_type: str = SOURCE_TYPE_GPS,
-        consider_home: timedelta = None,
-    ):
+        consider_home: timedelta | None = None,
+    ) -> None:
         """Mark the device as seen."""
         self.source_type = source_type
         self.last_seen = dt_util.utcnow()
@@ -708,9 +714,9 @@ class Device(RestoreEntity):
         self.location_name = location_name
         self.consider_home = consider_home or self.consider_home
 
-        if battery:
+        if battery is not None:
             self.battery = battery
-        if attributes:
+        if attributes is not None:
             self._attributes.update(attributes)
 
         self.gps = None
@@ -726,7 +732,7 @@ class Device(RestoreEntity):
 
         await self.async_update()
 
-    def stale(self, now: dt_util.dt.datetime = None):
+    def stale(self, now: dt_util.dt.datetime | None = None) -> bool:
         """Return if device state is stale.
 
         Async friendly.
@@ -795,7 +801,7 @@ class Device(RestoreEntity):
 class DeviceScanner:
     """Device scanner object."""
 
-    hass: HomeAssistant = None
+    hass: HomeAssistant | None = None
 
     def scan_devices(self) -> list[str]:
         """Scan for devices."""
@@ -803,14 +809,20 @@ class DeviceScanner:
 
     async def async_scan_devices(self) -> Any:
         """Scan for devices."""
+        assert (
+            self.hass is not None
+        ), "hass should be set by async_setup_scanner_platform"
         return await self.hass.async_add_executor_job(self.scan_devices)
 
-    def get_device_name(self, device: str) -> str:
+    def get_device_name(self, device: str) -> str | None:
         """Get the name of a device."""
         raise NotImplementedError()
 
-    async def async_get_device_name(self, device: str) -> Any:
+    async def async_get_device_name(self, device: str) -> str | None:
         """Get the name of a device."""
+        assert (
+            self.hass is not None
+        ), "hass should be set by async_setup_scanner_platform"
         return await self.hass.async_add_executor_job(self.get_device_name, device)
 
     def get_extra_attributes(self, device: str) -> dict:
@@ -819,6 +831,9 @@ class DeviceScanner:
 
     async def async_get_extra_attributes(self, device: str) -> Any:
         """Get the extra attributes of a device."""
+        assert (
+            self.hass is not None
+        ), "hass should be set by async_setup_scanner_platform"
         return await self.hass.async_add_executor_job(self.get_extra_attributes, device)
 
 
@@ -868,7 +883,7 @@ async def async_load_config(path: str, hass: HomeAssistant, consider_home: timed
 def update_config(path: str, dev_id: str, device: Device):
     """Add device to YAML configuration file."""
     with open(path, "a") as out:
-        device = {
+        device_config = {
             device.dev_id: {
                 ATTR_NAME: device.name,
                 ATTR_MAC: device.mac,
@@ -878,7 +893,7 @@ def update_config(path: str, dev_id: str, device: Device):
             }
         }
         out.write("\n")
-        out.write(dump(device))
+        out.write(dump(device_config))
 
 
 def get_gravatar_for_email(email: str):
diff --git a/mypy.ini b/mypy.ini
index b2590348431..13f88680ae9 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -816,9 +816,6 @@ ignore_errors = true
 [mypy-homeassistant.components.denonavr.*]
 ignore_errors = true
 
-[mypy-homeassistant.components.device_tracker.*]
-ignore_errors = true
-
 [mypy-homeassistant.components.devolo_home_control.*]
 ignore_errors = true
 
diff --git a/script/hassfest/mypy_config.py b/script/hassfest/mypy_config.py
index dd9e6c521fa..94f5bc81a0d 100644
--- a/script/hassfest/mypy_config.py
+++ b/script/hassfest/mypy_config.py
@@ -44,7 +44,6 @@ IGNORED_MODULES: Final[list[str]] = [
     "homeassistant.components.deconz.*",
     "homeassistant.components.demo.*",
     "homeassistant.components.denonavr.*",
-    "homeassistant.components.device_tracker.*",
     "homeassistant.components.devolo_home_control.*",
     "homeassistant.components.dhcp.*",
     "homeassistant.components.directv.*",
diff --git a/tests/components/mqtt/test_device_tracker_discovery.py b/tests/components/mqtt/test_device_tracker_discovery.py
index f158a878fcd..174db8f017a 100644
--- a/tests/components/mqtt/test_device_tracker_discovery.py
+++ b/tests/components/mqtt/test_device_tracker_discovery.py
@@ -359,4 +359,4 @@ async def test_setting_device_tracker_location_via_lat_lon_message(
     async_fire_mqtt_message(hass, "attributes-topic", '{"latitude":32.87336}')
     state = hass.states.get("device_tracker.test")
     assert state.attributes["latitude"] == 32.87336
-    assert state.state == STATE_NOT_HOME
+    assert state.state == STATE_UNKNOWN