diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1979,6 +1979,9 @@
     'PhabricatorCustomFieldAttachment' => 'infrastructure/customfield/field/PhabricatorCustomFieldAttachment.php',
     'PhabricatorCustomFieldConfigOptionType' => 'infrastructure/customfield/config/PhabricatorCustomFieldConfigOptionType.php',
     'PhabricatorCustomFieldDataNotAvailableException' => 'infrastructure/customfield/exception/PhabricatorCustomFieldDataNotAvailableException.php',
+    'PhabricatorCustomFieldEditEngineExtension' => 'infrastructure/customfield/editor/PhabricatorCustomFieldEditEngineExtension.php',
+    'PhabricatorCustomFieldEditField' => 'infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php',
+    'PhabricatorCustomFieldEditType' => 'infrastructure/customfield/editor/PhabricatorCustomFieldEditType.php',
     'PhabricatorCustomFieldHeraldField' => 'infrastructure/customfield/herald/PhabricatorCustomFieldHeraldField.php',
     'PhabricatorCustomFieldHeraldFieldGroup' => 'infrastructure/customfield/herald/PhabricatorCustomFieldHeraldFieldGroup.php',
     'PhabricatorCustomFieldImplementationIncompleteException' => 'infrastructure/customfield/exception/PhabricatorCustomFieldImplementationIncompleteException.php',
@@ -6065,6 +6068,9 @@
     'PhabricatorCustomFieldAttachment' => 'Phobject',
     'PhabricatorCustomFieldConfigOptionType' => 'PhabricatorConfigOptionType',
     'PhabricatorCustomFieldDataNotAvailableException' => 'Exception',
+    'PhabricatorCustomFieldEditEngineExtension' => 'PhabricatorEditEngineExtension',
+    'PhabricatorCustomFieldEditField' => 'PhabricatorEditField',
+    'PhabricatorCustomFieldEditType' => 'PhabricatorEditType',
     'PhabricatorCustomFieldHeraldField' => 'HeraldField',
     'PhabricatorCustomFieldHeraldFieldGroup' => 'HeraldFieldGroup',
     'PhabricatorCustomFieldImplementationIncompleteException' => 'Exception',
diff --git a/src/applications/transactions/editfield/PhabricatorEditField.php b/src/applications/transactions/editfield/PhabricatorEditField.php
--- a/src/applications/transactions/editfield/PhabricatorEditField.php
+++ b/src/applications/transactions/editfield/PhabricatorEditField.php
@@ -145,10 +145,6 @@
     return $this->isHidden;
   }
 
-  protected function newControl() {
-    throw new PhutilMethodNotImplementedException();
-  }
-
   public function setIsSubmittedForm($is_submitted) {
     $this->isSubmittedForm = $is_submitted;
     return $this;
@@ -176,7 +172,11 @@
     return $this->controlError;
   }
 
-  protected function renderControl() {
+  protected function newControl() {
+    throw new PhutilMethodNotImplementedException();
+  }
+
+  protected function buildControl() {
     $control = $this->newControl();
     if ($control === null) {
       return null;
@@ -190,6 +190,24 @@
       $control->setLabel($this->getLabel());
     }
 
+    if ($this->getIsSubmittedForm()) {
+      $error = $this->getControlError();
+      if ($error !== null) {
+        $control->setError($error);
+      }
+    } else if ($this->getIsRequired()) {
+      $control->setError(true);
+    }
+
+    return $control;
+  }
+
+  protected function renderControl() {
+    $control = $this->buildControl();
+    if ($control === null) {
+      return null;
+    }
+
     if ($this->getIsPreview()) {
       $disabled = true;
       $hidden = false;
@@ -207,16 +225,6 @@
 
     $control->setDisabled($disabled);
 
-
-    if ($this->getIsSubmittedForm()) {
-      $error = $this->getControlError();
-      if ($error !== null) {
-        $control->setError($error);
-      }
-    } else if ($this->getIsRequired()) {
-      $control->setError(true);
-    }
-
     return $control;
   }
 
diff --git a/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditEngineExtension.php b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditEngineExtension.php
new file mode 100644
--- /dev/null
+++ b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditEngineExtension.php
@@ -0,0 +1,50 @@
+<?php
+
+final class PhabricatorCustomFieldEditEngineExtension
+  extends PhabricatorEditEngineExtension {
+
+  const EXTENSIONKEY = 'customfield.fields';
+
+  public function getExtensionPriority() {
+    return 5000;
+  }
+
+  public function isExtensionEnabled() {
+    return true;
+  }
+
+  public function getExtensionName() {
+    return pht('Custom Fields');
+  }
+
+  public function supportsObject(
+    PhabricatorEditEngine $engine,
+    PhabricatorApplicationTransactionInterface $object) {
+    return ($object instanceof PhabricatorCustomFieldInterface);
+  }
+
+  public function buildCustomEditFields(
+    PhabricatorEditEngine $engine,
+    PhabricatorApplicationTransactionInterface $object) {
+
+    $viewer = $this->getViewer();
+
+    $field_list = PhabricatorCustomField::getObjectFields(
+      $object,
+      PhabricatorCustomField::ROLE_EDIT);
+
+    $field_list->setViewer($viewer);
+    $field_list->readFieldsFromStorage($object);
+
+    $results = array();
+    foreach ($field_list->getFields() as $field) {
+      $edit_fields = $field->getEditEngineFields($engine);
+      foreach ($edit_fields as $edit_field) {
+        $results[] = $edit_field;
+      }
+    }
+
+    return $results;
+  }
+
+}
diff --git a/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php
new file mode 100644
--- /dev/null
+++ b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php
@@ -0,0 +1,73 @@
+<?php
+
+final class PhabricatorCustomFieldEditField
+  extends PhabricatorEditField {
+
+  private $customField;
+
+  public function setCustomField(PhabricatorCustomField $custom_field) {
+    $this->customField = $custom_field;
+    return $this;
+  }
+
+  public function getCustomField() {
+    return $this->customField;
+  }
+
+  protected function buildControl() {
+    $field = $this->getCustomField();
+    $clone = clone $field;
+
+    if ($this->getIsSubmittedForm()) {
+      $value = $this->getValue();
+      $clone->setValueFromApplicationTransactions($value);
+    }
+
+    return $clone->renderEditControl(array());
+  }
+
+  protected function newEditType() {
+    return id(new PhabricatorCustomFieldEditType())
+      ->setCustomField($this->getCustomField());
+  }
+
+  public function getValueForTransaction() {
+    $value = $this->getValue();
+    $field = $this->getCustomField();
+
+    // Avoid changing the value of the field itself, since later calls would
+    // incorrectly reflect the new value.
+    $clone = clone $field;
+    $clone->setValueFromApplicationTransactions($value);
+    return $clone->getNewValueForApplicationTransactions();
+  }
+
+  protected function getValueExistsInRequest(AphrontRequest $request, $key) {
+    // For now, never read these out of the request.
+    return false;
+  }
+
+  protected function getValueExistsInSubmit(AphrontRequest $request, $key) {
+    return true;
+  }
+
+  protected function getValueFromSubmit(AphrontRequest $request, $key) {
+    $field = $this->getCustomField();
+
+    $clone = clone $field;
+
+    $clone->readValueFromRequest($request);
+    return $clone->getNewValueForApplicationTransactions();
+  }
+
+  public function getConduitEditTypes() {
+    // TODO: For now, don't support custom fields over Conduit.
+    return array();
+  }
+
+  protected function newHTTPParameterType() {
+    // TODO: For now, don't support custom fields for HTTP prefill.
+    return null;
+  }
+
+}
diff --git a/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditType.php b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditType.php
new file mode 100644
--- /dev/null
+++ b/src/infrastructure/customfield/editor/PhabricatorCustomFieldEditType.php
@@ -0,0 +1,53 @@
+<?php
+
+final class PhabricatorCustomFieldEditType
+  extends PhabricatorEditType {
+
+  private $customField;
+
+  public function setCustomField(PhabricatorCustomField $custom_field) {
+    $this->customField = $custom_field;
+    return $this;
+  }
+
+  public function getCustomField() {
+    return $this->customField;
+  }
+
+  public function getValueType() {
+    // TODO: Improve.
+    return 'custom';
+  }
+
+  public function getMetadata() {
+    $field = $this->getCustomField();
+    return parent::getMetadata() + $field->getApplicationTransactionMetadata();
+  }
+
+  public function getValueDescription() {
+    $field = $this->getCustomField();
+    return $field->getFieldDescription();
+  }
+
+  public function generateTransactions(
+    PhabricatorApplicationTransaction $template,
+    array $spec) {
+
+    $value = idx($spec, 'value');
+
+    $xaction = $this->newTransaction($template)
+      ->setNewValue($value);
+
+    $custom_type = PhabricatorTransactions::TYPE_CUSTOMFIELD;
+    if ($xaction->getTransactionType() == $custom_type) {
+      $field = $this->getCustomField();
+
+      $xaction
+        ->setOldValue($field->getOldValueForApplicationTransactions())
+        ->setMetadataValue('customfield:key', $field->getFieldKey());
+    }
+
+    return array($xaction);
+  }
+
+}
diff --git a/src/infrastructure/customfield/field/PhabricatorCustomField.php b/src/infrastructure/customfield/field/PhabricatorCustomField.php
--- a/src/infrastructure/customfield/field/PhabricatorCustomField.php
+++ b/src/infrastructure/customfield/field/PhabricatorCustomField.php
@@ -1082,6 +1082,33 @@
 /* -(  Edit View  )---------------------------------------------------------- */
 
 
+  public function getEditEngineFields(PhabricatorEditEngine $engine) {
+    $field = $this->newStandardEditField($engine);
+
+    return array(
+      $field,
+    );
+  }
+
+  protected function newEditField() {
+    return id(new PhabricatorCustomFieldEditField())
+      ->setCustomField($this);
+  }
+
+  protected function newStandardEditField() {
+    if ($this->proxy) {
+      return $this->proxy->newStandardEditField();
+    }
+
+    return $this->newEditField()
+      ->setKey($this->getFieldKey())
+      ->setEditTypeKey('custom.'.$this->getFieldKey())
+      ->setLabel($this->getFieldName())
+      ->setDescription($this->getFieldDescription())
+      ->setTransactionType($this->getApplicationTransactionType())
+      ->setValue($this->getNewValueForApplicationTransactions());
+  }
+
   /**
    * @task edit
    */
diff --git a/src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php b/src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php
--- a/src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php
+++ b/src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php
@@ -426,4 +426,11 @@
     }
   }
 
+  protected function newStandardEditField() {
+    $short = 'custom.'.$this->getRawStandardFieldKey();
+
+    return parent::newStandardEditField()
+      ->setEditTypeKey($short);
+  }
+
 }