diff --git a/changelog.d/20389.bugfix b/changelog.d/20389.bugfix
new file mode 100644
index 0000000000..78ad1f0f16
--- /dev/null
+++ b/changelog.d/20389.bugfix
@@ -0,0 +1 @@
+Fix a bug introduced in Synapse v1.30.0 where `synapse.logging.RemoteHandler` stopped sending logs shortly after connecting. Thanks to @haarp for the diagnosis.
diff --git a/synapse/logging/_remote.py b/synapse/logging/_remote.py
index b10c3b9b01..a5241a8ae9 100644
--- a/synapse/logging/_remote.py
+++ b/synapse/logging/_remote.py
@@ -198,9 +198,11 @@ class RemoteHandler(logging.Handler):
             self._producer.resumeProducing()
             self._connection_waiter = None
 
+        # Set the waiter before adding callbacks: if we are already connected
+        # they run synchronously and clear it again.
         deferred: Deferred = self._service.whenConnected(failAfterFailures=1)
-        deferred.addCallbacks(writer, fail)
         self._connection_waiter = deferred
+        deferred.addCallbacks(writer, fail)
 
     def _handle_pressure(self) -> None:
         """
diff --git a/tests/logging/test_remote_handler.py b/tests/logging/test_remote_handler.py
index 68bdc28573..1a38268413 100644
--- a/tests/logging/test_remote_handler.py
+++ b/tests/logging/test_remote_handler.py
@@ -75,6 +75,31 @@ class RemoteHandlerTestCase(LoggerCleanupMixin, TestCase):
         # Ensure the data passed through properly.
         self.assertEqual(logs[0], "Hello there, wally!")
 
+    def test_log_output_after_connecting(self) -> None:
+        """
+        The remote handler keeps delivering logs once it is connected.
+        """
+        handler = RemoteHandler("127.0.0.1", 9000, _reactor=self.reactor)
+        logger = self.get_logger(handler)
+
+        logger.info("Hello there, %s!", "wally")
+
+        # Trigger the connection
+        client, server = connect_logging_client(self.reactor, 0)
+        client_transport = checked_cast(FakeTransport, client.transport)
+        client_transport.flush()
+
+        # Log over the existing connection
+        for i in range(3):
+            logger.info("more %s", i)
+            client_transport.flush()
+
+        logs = server.data.decode("utf8").splitlines()
+        self.assertEqual(
+            ["Hello there, wally!", "more 0", "more 1", "more 2"],
+            logs,
+        )
+
     def test_log_backpressure_debug(self) -> None:
         """
         When backpressure is hit, DEBUG logs will be shed.