diff --git a/.changeset/fifty-planes-dream.md b/.changeset/fifty-planes-dream.md
new file mode 100644
index 0000000000..655cd42dc1
--- /dev/null
+++ b/.changeset/fifty-planes-dream.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-auth-backend': patch
+---
+
+Increased key field size for signing_keys table to account for larger signature keys
diff --git a/plugins/auth-backend/migrations/20220522100910_key_field_size.js b/plugins/auth-backend/migrations/20220522100910_key_field_size.js
new file mode 100644
index 0000000000..c27d038223
--- /dev/null
+++ b/plugins/auth-backend/migrations/20220522100910_key_field_size.js
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2022 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// @ts-check
+
+/**
+ * @param {import('knex').Knex} knex
+ */
+exports.up = async function up(knex) {
+  // Sqlite does not support alter column.
+  if (!knex.client.config.client.includes('sqlite3')) {
+    await knex.schema.alterTable('signing_keys', table => {
+      table
+        .text('key')
+        .notNullable()
+        .comment('The serialized signing key')
+        .alter({ alterType: true });
+    });
+  }
+};
+
+/**
+ * @param {import('knex').Knex} knex
+ */
+exports.down = async function down(knex) {
+  // Sqlite does not support alter column.
+  if (!knex.client.config.client.includes('sqlite3')) {
+    await knex.schema.alterTable('signing_keys', table => {
+      table
+        .string('key')
+        .notNullable()
+        .comment('The serialized signing key')
+        .alter({ alterType: true });
+    });
+  }
+};
diff --git a/plugins/auth-backend/src/identity/TokenFactory.ts b/plugins/auth-backend/src/identity/TokenFactory.ts
index fe9d2a1b4f..44cfebfb71 100644
--- a/plugins/auth-backend/src/identity/TokenFactory.ts
+++ b/plugins/auth-backend/src/identity/TokenFactory.ts
@@ -34,6 +34,9 @@ type Options = {
   keyDurationSeconds: number;
   /** JWS "alg" (Algorithm) Header Parameter value. Defaults to ES256.
    * Must match one of the algorithms defined for IdentityClient.
+   * When setting a different algorithm, check if the `key` field
+   * of the `signing_keys` table can fit the length of the generated keys.
+   * If not, add a knex migration file in the migrations folder.
    * More info on supported algorithms: https://github.com/panva/jose */
   algorithm?: string;
 };