diff --git a/plugins/wporg-5ftf/includes/pledge-log.php b/plugins/wporg-5ftf/includes/pledge-log.php
new file mode 100644
index 0000000..1a7f643
--- /dev/null
+++ b/plugins/wporg-5ftf/includes/pledge-log.php
@@ -0,0 +1,165 @@
+<?php
+namespace WordPressDotOrg\FiveForTheFuture\PledgeLog;
+
+use WordPressDotOrg\FiveForTheFuture;
+use WordPressDotOrg\FiveForTheFuture\{ Contributor, Pledge, PledgeForm, PledgeMeta };
+use WP_Post;
+
+defined( 'WPINC' ) || die();
+
+const LOG_META_KEY = FiveForTheFuture\PREFIX . '_activity-log';
+
+// Log display.
+add_action( 'admin_init', __NAMESPACE__ . '\add_log_meta_box' );
+
+// Log capture.
+add_action( 'save_post_' . Pledge\CPT_ID, __NAMESPACE__ . '\capture_save_post', 99, 3 );
+add_action( 'updated_postmeta', __NAMESPACE__ . '\capture_updated_postmeta', 99, 4 );
+
+/**
+ * Adds a meta box for the log on the custom post type.
+ *
+ * @return void
+ */
+function add_log_meta_box() {
+	add_meta_box(
+		'activity-log',
+		__( 'Log', 'wordpressorg' ),
+		__NAMESPACE__ . '\render_log_meta_box',
+		Pledge\CPT_ID,
+		'advanced',
+		'low'
+	);
+}
+
+/**
+ * Output the log in the meta box.
+ *
+ * @param WP_Post $pledge
+ *
+ * @return void
+ */
+function render_log_meta_box( $pledge ) {
+	$log = get_pledge_log( $pledge->ID );
+
+	require FiveForTheFuture\get_views_path() . 'log.php';
+}
+
+/**
+ * Defaults for a log entry.
+ *
+ * @return array
+ */
+function get_log_entry_template() {
+	return array(
+		'timestamp' => time(),
+		'message'   => '',
+		'data'      => array(),
+		'user_id'   => 0,
+	);
+}
+
+/**
+ * Get a time-sorted array of log entries for a particular pledge.
+ *
+ * @param int $pledge_id
+ *
+ * @return array
+ */
+function get_pledge_log( $pledge_id ) {
+	$log = get_post_meta( $pledge_id, LOG_META_KEY, false );
+
+	if ( ! $log ) {
+		return array();
+	}
+
+	usort( $log, function( $a, $b ) {
+		if ( $a['timestamp'] === $b['timestamp'] ) {
+			return 0;
+		}
+
+		return ( $a['timestamp'] < $b['timestamp'] ) ? -1 : 1;
+	} );
+
+	return $log;
+}
+
+/**
+ * Add a new log entry for a particular pledge.
+ *
+ * @param int    $pledge_id
+ * @param string $message
+ * @param array  $data
+ * @param int    $user_id
+ *
+ * @return void
+ */
+function add_log_entry( $pledge_id, $message, array $data, $user_id ) {
+	$entry = get_log_entry_template();
+
+	$entry['message'] = $message;
+	$entry['data']    = $data;
+	$entry['user_id'] = $user_id;
+
+	add_post_meta( $pledge_id, LOG_META_KEY, $entry, false );
+}
+
+/**
+ * Record logs for events when saving a post.
+ *
+ * Hooked to "save_post_{$post->post_type}".
+ *
+ * @param int     $post_ID Post ID.
+ * @param WP_Post $post    Unused. Post object.
+ * @param bool    $update  Whether this is an existing post being updated or not.
+ *
+ * @return void
+ */
+function capture_save_post( $post_ID, $post, $update ) {
+	if ( false === $update ) {
+		add_log_entry(
+			$post_ID,
+			sprintf(
+				'Pledge created. Status set to <code>%s</code>.',
+				esc_html( get_post_status( $post_ID ) )
+			),
+			PledgeForm\get_form_submission(),
+			get_current_user_id()
+		);
+	}
+}
+
+/**
+ * Record logs for events when postmeta values change.
+ *
+ * @param int    $meta_id    Unused. ID of updated metadata entry.
+ * @param int    $object_id  Post ID.
+ * @param string $meta_key   Meta key.
+ * @param mixed  $meta_value Meta value.
+ *
+ * @return void
+ */
+function capture_updated_postmeta( $meta_id, $object_id, $meta_key, $meta_value ) {
+	$post_type = get_post_type( $object_id );
+
+	if ( Pledge\CPT_ID !== $post_type ) {
+		return;
+	}
+
+	$valid_keys = array_keys( PledgeMeta\get_pledge_meta_config( 'user_input' ) );
+
+	if ( in_array( $meta_key, $valid_keys, true ) ) {
+		add_log_entry(
+			$object_id,
+			sprintf(
+				'Changed <code>%1$s</code>code> to <code>%2$s</code>.',
+				esc_html( $meta_key ),
+				esc_html( $meta_value )
+			),
+			array(
+				$meta_key => $meta_value,
+			),
+			get_current_user_id()
+		);
+	}
+}
diff --git a/plugins/wporg-5ftf/index.php b/plugins/wporg-5ftf/index.php
index 54e1d28..be8c836 100755
--- a/plugins/wporg-5ftf/index.php
+++ b/plugins/wporg-5ftf/index.php
@@ -30,6 +30,7 @@ function load() {
 	require_once get_includes_path() . 'pledge-form.php';
 	require_once get_includes_path() . 'directory.php';
 	require_once get_includes_path() . 'xprofile.php';
+	require_once get_includes_path() . 'pledge-log.php';
 }
 
 /**
diff --git a/plugins/wporg-5ftf/views/log.php b/plugins/wporg-5ftf/views/log.php
new file mode 100644
index 0000000..57d3fcb
--- /dev/null
+++ b/plugins/wporg-5ftf/views/log.php
@@ -0,0 +1,53 @@
+<?php
+namespace WordPressDotOrg\FiveForTheFuture\View;
+
+/** @var array $log */
+?>
+
+<div class="5ftf-activity-log">
+	<?php if ( ! empty( $log ) ) : ?>
+
+		<table class="striped widefat">
+			<thead>
+			<tr>
+				<td>Date</td>
+				<td>Entry</td>
+				<td>User</td>
+			</tr>
+			</thead>
+			<tbody>
+			<?php foreach ( $log as $entry ) : ?>
+				<tr>
+					<td>
+						<?php echo esc_html( date( 'Y-m-d G:i:s', $entry['timestamp'] ) ); ?>
+					</td>
+					<td>
+						<details>
+							<summary>
+								<?php echo wp_kses_data( $entry['message'] ); ?>
+							</summary>
+							<?php if ( ! empty( $entry['data'] ) ) : ?>
+								<pre><?php echo esc_html( print_r( $entry['data'] ) ); ?></pre>
+							<?php endif; ?>
+						</details>
+					</td>
+					<td>
+						<?php
+						$user = get_user_by( 'id', $entry['user_id'] );
+						if ( $user ) : ?>
+							<?php echo sanitize_user( $user->user_login ); ?>
+						<?php endif; ?>
+					</td>
+				</tr>
+			<?php endforeach; ?>
+			</tbody>
+		</table>
+
+	<?php else : ?>
+
+		<p>
+			There are no log entries.
+		</p>
+
+	<?php endif; ?>
+</div>