diff --git a/dist/index.js b/dist/index.js
index 8576ed4..ce53ef1 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -551,6 +551,7 @@ const url_1 = __nccwpck_require__(7310);
 const utils = __importStar(__nccwpck_require__(918));
 class GitAuthHelper {
     constructor(git) {
+        this.gitConfigPath = '';
         this.safeDirectoryConfigKey = 'safe.directory';
         this.safeDirectoryAdded = false;
         this.extraheaderConfigPlaceholderValue = 'AUTHORIZATION: basic ***';
@@ -558,7 +559,6 @@ class GitAuthHelper {
         this.persistedExtraheaderConfigValue = '';
         this.git = git;
         this.workingDirectory = this.git.getWorkingDirectory();
-        this.gitConfigPath = path.join(this.workingDirectory, '.git', 'config');
         const serverUrl = this.getServerUrl();
         this.extraheaderConfigKey = `http.${serverUrl.origin}/.extraheader`;
     }
@@ -640,6 +640,10 @@ class GitAuthHelper {
     }
     gitConfigStringReplace(find, replace) {
         return __awaiter(this, void 0, void 0, function* () {
+            if (this.gitConfigPath.length === 0) {
+                const gitDir = yield this.git.getGitDirectory();
+                this.gitConfigPath = path.join(this.workingDirectory, gitDir, 'config');
+            }
             let content = (yield fs.promises.readFile(this.gitConfigPath)).toString();
             const index = content.indexOf(find);
             if (index < 0 || index != content.lastIndexOf(find)) {
@@ -818,6 +822,9 @@ class GitCommandManager {
             return output.stdout.trim().split(`${configKey} `)[1];
         });
     }
+    getGitDirectory() {
+        return this.revParse('--git-dir');
+    }
     getWorkingDirectory() {
         return this.workingDirectory;
     }
diff --git a/docs/updating.md b/docs/updating.md
index 5df1c68..f798dc5 100644
--- a/docs/updating.md
+++ b/docs/updating.md
@@ -11,6 +11,7 @@
 - Any uncommitted tracked or untracked changes are now stashed and restored at the end of the action run. Currently, this can only occur when using the `add-paths` input, which allows for changes to not be committed. Previously, any uncommitted changes would be destroyed.
 - The proxy implementation has been revised but is not expected to have any change in behaviour. It continues to support the standard environment variables `http_proxy`, `https_proxy` and `no_proxy`.
 - The action now sets the git `safe.directory` configuration for the local repository path. The configuration is removed when the action completes. Fixes issue https://github.com/peter-evans/create-pull-request/issues/1170.
+- The action now determines the git directory path using the `git rev-parse --git-dir` command. This allows users with custom repository configurations to use the action.
 
 ## Updating from `v3` to `v4`
 
diff --git a/src/git-auth-helper.ts b/src/git-auth-helper.ts
index 885a96c..80fc5f3 100644
--- a/src/git-auth-helper.ts
+++ b/src/git-auth-helper.ts
@@ -7,7 +7,7 @@ import * as utils from './utils'
 
 export class GitAuthHelper {
   private git: GitCommandManager
-  private gitConfigPath: string
+  private gitConfigPath = ''
   private workingDirectory: string
   private safeDirectoryConfigKey = 'safe.directory'
   private safeDirectoryAdded = false
@@ -19,7 +19,6 @@ export class GitAuthHelper {
   constructor(git: GitCommandManager) {
     this.git = git
     this.workingDirectory = this.git.getWorkingDirectory()
-    this.gitConfigPath = path.join(this.workingDirectory, '.git', 'config')
     const serverUrl = this.getServerUrl()
     this.extraheaderConfigKey = `http.${serverUrl.origin}/.extraheader`
   }
@@ -133,6 +132,10 @@ export class GitAuthHelper {
     find: string,
     replace: string
   ): Promise<void> {
+    if (this.gitConfigPath.length === 0) {
+      const gitDir = await this.git.getGitDirectory()
+      this.gitConfigPath = path.join(this.workingDirectory, gitDir, 'config')
+    }
     let content = (await fs.promises.readFile(this.gitConfigPath)).toString()
     const index = content.indexOf(find)
     if (index < 0 || index != content.lastIndexOf(find)) {
diff --git a/src/git-command-manager.ts b/src/git-command-manager.ts
index 3705474..b77f078 100644
--- a/src/git-command-manager.ts
+++ b/src/git-command-manager.ts
@@ -146,6 +146,10 @@ export class GitCommandManager {
     return output.stdout.trim().split(`${configKey} `)[1]
   }
 
+  getGitDirectory(): Promise<string> {
+    return this.revParse('--git-dir')
+  }
+
   getWorkingDirectory(): string {
     return this.workingDirectory
   }