diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 9bb54b2..aa6462b 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -27,8 +27,6 @@
 QUIC_FLAG(FLAGS_quic_restart_flag_quic_support_release_time_for_gso, false)
 // If true, QuicIdleNetworkDetector::SetAlarm will become a noop if dectection has been stopped by QuicIdleNetworkDetector::StopDetection.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_idle_network_detector_no_alarm_after_stopped, true)
-// If true, TlsServerHandshaker::DefaultProofSourceHandle::DefaultSignatureCallback will run at most once.
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_run_default_signature_callback_once, true)
 // If true, abort async QPACK header decompression in QuicSpdyStream::Reset() and in QuicSpdyStream::OnStreamReset().
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_abort_qpack_on_stream_reset, true)
 // If true, ack frequency frame can be sent from server to client.
diff --git a/quic/core/tls_server_handshaker.h b/quic/core/tls_server_handshaker.h
index 998cc15..515c813 100644
--- a/quic/core/tls_server_handshaker.h
+++ b/quic/core/tls_server_handshaker.h
@@ -259,22 +259,12 @@
           return;
         }
 
-        if (GetQuicReloadableFlag(quic_run_default_signature_callback_once)) {
-          QUIC_RELOADABLE_FLAG_COUNT(quic_run_default_signature_callback_once);
-          DefaultProofSourceHandle* handle = handle_;
-          handle_ = nullptr;
+        DefaultProofSourceHandle* handle = handle_;
+        handle_ = nullptr;
 
-          handle->signature_callback_ = nullptr;
-          if (handle->handshaker_ != nullptr) {
-            handle->handshaker_->OnComputeSignatureDone(
-                ok, is_sync_, std::move(signature), std::move(details));
-          }
-          return;
-        }
-
-        handle_->signature_callback_ = nullptr;
-        if (handle_->handshaker_ != nullptr) {
-          handle_->handshaker_->OnComputeSignatureDone(
+        handle->signature_callback_ = nullptr;
+        if (handle->handshaker_ != nullptr) {
+          handle->handshaker_->OnComputeSignatureDone(
               ok, is_sync_, std::move(signature), std::move(details));
         }
       }