diff --git a/tools/internal_ci/linux/pull_request/grpc_microbenchmark_diff.cfg b/tools/internal_ci/linux/pull_request/grpc_microbenchmark_diff.cfg
index 47301d61415..3c62401cc3a 100644
--- a/tools/internal_ci/linux/pull_request/grpc_microbenchmark_diff.cfg
+++ b/tools/internal_ci/linux/pull_request/grpc_microbenchmark_diff.cfg
@@ -17,6 +17,14 @@
 # Location of the continuous shell script in repository.
 build_file: "grpc/tools/internal_ci/linux/grpc_microbenchmark_diff.sh"
 timeout_mins: 120
+before_action {
+  fetch_keystore {
+    keystore_resource {
+      keystore_config_id: 73836
+      keyname: "grpc_checks_private_key"
+    }
+  }
+}
 action {
   define_artifacts {
     regex: "**/*sponge_log.*"
diff --git a/tools/internal_ci/linux/pull_request/grpc_trickle_diff.cfg b/tools/internal_ci/linux/pull_request/grpc_trickle_diff.cfg
index 78358eac28e..69e44276625 100644
--- a/tools/internal_ci/linux/pull_request/grpc_trickle_diff.cfg
+++ b/tools/internal_ci/linux/pull_request/grpc_trickle_diff.cfg
@@ -17,6 +17,14 @@
 # Location of the continuous shell script in repository.
 build_file: "grpc/tools/internal_ci/linux/grpc_trickle_diff.sh"
 timeout_mins: 120
+before_action {
+  fetch_keystore {
+    keystore_resource {
+      keystore_config_id: 73836
+      keyname: "grpc_checks_private_key"
+    }
+  }
+}
 action {
   define_artifacts {
     regex: "**/*sponge_log.*"
diff --git a/tools/internal_ci/macos/pull_request/grpc_ios_binary_size.cfg b/tools/internal_ci/macos/pull_request/grpc_ios_binary_size.cfg
index fb215bdf994..1c4f7b23109 100644
--- a/tools/internal_ci/macos/pull_request/grpc_ios_binary_size.cfg
+++ b/tools/internal_ci/macos/pull_request/grpc_ios_binary_size.cfg
@@ -18,6 +18,14 @@
 build_file: "grpc/tools/internal_ci/macos/grpc_ios_binary_size.sh"
 timeout_mins: 60
 gfile_resources: "/bigstore/grpc-testing-secrets/github_credentials/oauth_token.txt"
+before_action {
+  fetch_keystore {
+    keystore_resource {
+      keystore_config_id: 73836
+      keyname: "grpc_checks_private_key"
+    }
+  }
+}
 action {
   define_artifacts {
     regex: "**/*sponge_log.*"
diff --git a/tools/run_tests/python_utils/check_on_pr.py b/tools/run_tests/python_utils/check_on_pr.py
index f756e4bdaa4..78f1dca817d 100644
--- a/tools/run_tests/python_utils/check_on_pr.py
+++ b/tools/run_tests/python_utils/check_on_pr.py
@@ -26,8 +26,8 @@ _GITHUB_REPO = 'grpc/grpc'
 _GITHUB_APP_ID = 22338
 _INSTALLATION_ID = 519109
 _GITHUB_APP_KEY = open(
-    os.environ['HOME'] + '/.ssh/google-grpc-checker.2018-12-13.private-key.pem',
-    'r').read()
+    os.path.join(os.environ['KOKORO_KEYSTORE_DIR'], '73836_grpc_checks_private_key'),
+    'rb').read()
 
 _ACCESS_TOKEN_CACHE = None