diff --git a/src/applications/differential/harbormaster/DifferentialBuildableEngine.php b/src/applications/differential/harbormaster/DifferentialBuildableEngine.php
--- a/src/applications/differential/harbormaster/DifferentialBuildableEngine.php
+++ b/src/applications/differential/harbormaster/DifferentialBuildableEngine.php
@@ -54,4 +54,28 @@
     $this->applyTransactions(array($xaction));
   }
 
+  public function getAuthorIdentity() {
+    $object = $this->getObject();
+
+    if ($object instanceof DifferentialRevision) {
+      $object = $object->loadActiveDiff();
+    }
+
+    $authorship = $object->getDiffAuthorshipDict();
+    if (!isset($authorship['authorName'])) {
+      return null;
+    }
+
+    $name = $authorship['authorName'];
+    $address = idx($authorship, 'authorEmail');
+
+    $full = id(new PhutilEmailAddress())
+      ->setDisplayName($name)
+      ->setAddress($address);
+
+    return id(new PhabricatorRepositoryIdentity())
+      ->setIdentityName((string)$full)
+      ->makeEphemeral();
+  }
+
 }
diff --git a/src/applications/diffusion/harbormaster/DiffusionBuildableEngine.php b/src/applications/diffusion/harbormaster/DiffusionBuildableEngine.php
--- a/src/applications/diffusion/harbormaster/DiffusionBuildableEngine.php
+++ b/src/applications/diffusion/harbormaster/DiffusionBuildableEngine.php
@@ -34,4 +34,10 @@
     $this->applyTransactions(array($xaction));
   }
 
+  public function getAuthorIdentity() {
+    return $this->getObject()
+      ->loadIdentities($this->getViewer())
+      ->getAuthorIdentity();
+  }
+
 }
diff --git a/src/applications/harbormaster/engine/HarbormasterBuildableEngine.php b/src/applications/harbormaster/engine/HarbormasterBuildableEngine.php
--- a/src/applications/harbormaster/engine/HarbormasterBuildableEngine.php
+++ b/src/applications/harbormaster/engine/HarbormasterBuildableEngine.php
@@ -101,5 +101,8 @@
       $xactions);
   }
 
+  public function getAuthorIdentity() {
+    return null;
+  }
 
 }
diff --git a/src/applications/harbormaster/step/HarbormasterBuildkiteBuildStepImplementation.php b/src/applications/harbormaster/step/HarbormasterBuildkiteBuildStepImplementation.php
--- a/src/applications/harbormaster/step/HarbormasterBuildkiteBuildStepImplementation.php
+++ b/src/applications/harbormaster/step/HarbormasterBuildkiteBuildStepImplementation.php
@@ -117,6 +117,20 @@
       ),
     );
 
+    $engine = HarbormasterBuildableEngine::newForObject(
+      $object,
+      $viewer);
+
+    $author_identity = $engine->getAuthorIdentity();
+    if ($author_identity) {
+      $data_structure += array(
+        'author' => array(
+          'name' => $author_identity->getIdentityDisplayName(),
+          'email' => $author_identity->getIdentityEmailAddress(),
+        ),
+      );
+    }
+
     $json_data = phutil_json_encode($data_structure);
 
     $credential_phid = $this->getSetting('token');
diff --git a/src/applications/repository/storage/PhabricatorRepositoryCommit.php b/src/applications/repository/storage/PhabricatorRepositoryCommit.php
--- a/src/applications/repository/storage/PhabricatorRepositoryCommit.php
+++ b/src/applications/repository/storage/PhabricatorRepositoryCommit.php
@@ -200,6 +200,8 @@
 
     $this->authorIdentity = $author;
     $this->committerIdentity = $committer;
+
+    return $this;
   }
 
   public function getAuthorIdentity() {
@@ -485,6 +487,23 @@
     return null;
   }
 
+  public function loadIdentities(PhabricatorUser $viewer) {
+    if ($this->authorIdentity !== self::ATTACHABLE) {
+      return $this;
+    }
+
+    $commit = id(new DiffusionCommitQuery())
+      ->setViewer($viewer)
+      ->withIDs(array($this->getID()))
+      ->needIdentities(true)
+      ->executeOne();
+
+    $author_identity = $commit->getAuthorIdentity();
+    $committer_identity = $commit->getCommitterIdentity();
+
+    return $this->attachIdentities($author_identity, $committer_identity);
+  }
+
   public function hasCommitterIdentity() {
     return ($this->getCommitterIdentity() !== null);
   }
diff --git a/src/applications/repository/storage/PhabricatorRepositoryIdentity.php b/src/applications/repository/storage/PhabricatorRepositoryIdentity.php
--- a/src/applications/repository/storage/PhabricatorRepositoryIdentity.php
+++ b/src/applications/repository/storage/PhabricatorRepositoryIdentity.php
@@ -65,6 +65,16 @@
       $this->getIdentityNameEncoding());
   }
 
+  public function getIdentityEmailAddress() {
+    $address = new PhutilEmailAddress($this->getIdentityName());
+    return $address->getAddress();
+  }
+
+  public function getIdentityDisplayName() {
+    $address = new PhutilEmailAddress($this->getIdentityName());
+    return $address->getDisplayName();
+  }
+
   public function getIdentityShortName() {
     // TODO
     return $this->getIdentityName();