diff --git a/cmd/tusd/cli/composer.go b/cmd/tusd/cli/composer.go
index b7a635a51..281301121 100644
--- a/cmd/tusd/cli/composer.go
+++ b/cmd/tusd/cli/composer.go
@@ -77,12 +77,9 @@ func CreateComposer() {
 				"Please remove underscore from the value", Flags.GCSObjectPrefix)
 		}
 
-		// Derivce credentials from service account file path passed in
-		// GCS_SERVICE_ACCOUNT_FILE environment variable.
+		// Application Default Credentials discovery mechanism is attempted to fetch credentials,
+		// but an account file can be provided through the GCS_SERVICE_ACCOUNT_FILE environment variable.
 		gcsSAF := os.Getenv("GCS_SERVICE_ACCOUNT_FILE")
-		if gcsSAF == "" {
-			stderr.Fatalf("No service account file provided for Google Cloud Storage using the GCS_SERVICE_ACCOUNT_FILE environment variable.\n")
-		}
 
 		service, err := gcsstore.NewGCSService(gcsSAF)
 		if err != nil {
diff --git a/docs/_storage-backends/google-cloud-storage.md b/docs/_storage-backends/google-cloud-storage.md
index 34cf5e293..94158014b 100644
--- a/docs/_storage-backends/google-cloud-storage.md
+++ b/docs/_storage-backends/google-cloud-storage.md
@@ -6,11 +6,21 @@ nav_order: 5
 
 # Google Cloud Storage
 
-Tusd can store files directly on Google Cloud Storage. The uploaded file is directly transferred to S3 while the user is performing the upload without storing the entire file on disk first.
+Tusd can store files directly on Google Cloud Storage. The uploaded file is directly transferred to Storage Bucket while the user is performing the upload without storing the entire file on disk first.
 
 ## Configuration
 
-To enable this backend, you must supply the path to the corresponding account file using environment variables and specify the bucket name using `-gcs-bucket`, for example:
+To enable this backend, you must specify the bucket name using `-gcs-bucket`, for example:
+
+```bash
+$ tusd -gcs-bucket=my-test-bucket.com
+[tusd] Using 'gcs://my-test-bucket.com' as GCS bucket for storage.
+...
+```
+
+By default, [Application Default Credentials discovery mechanism](https://cloud.google.com/docs/authentication/external/set-up-adc) will be attempted.
+
+If `GCS_SERVICE_ACCOUNT_FILE` environment variable is provided, that account will be used instead:
 
 ```bash
 $ export GCS_SERVICE_ACCOUNT_FILE=./account.json
diff --git a/pkg/gcsstore/gcsservice.go b/pkg/gcsstore/gcsservice.go
index de9a00eff..9f50ef866 100644
--- a/pkg/gcsstore/gcsservice.go
+++ b/pkg/gcsstore/gcsservice.go
@@ -81,7 +81,12 @@ type GCSService struct {
 // NewGCSService returns a GCSService object given a GCloud service account file path.
 func NewGCSService(filename string) (*GCSService, error) {
 	ctx := context.Background()
-	client, err := storage.NewClient(ctx, option.WithCredentialsFile(filename))
+	var opts []option.ClientOption
+	if filename != "" {
+		opts = append(opts, option.WithCredentialsFile(filename))
+	}
+	client, err := storage.NewClient(ctx, opts...)
+
 	if err != nil {
 		return nil, err
 	}