About my code above. Notice the very first line:
/* Assuming that you have the $user object */
$profile = $user->getOne('Profile');
If you don’t already have the user object, you have to get it before calling getOne().
In the front end, that would be either this at the top:
$user = $modx->user;
or just changing the code to:
$profile = $modx->user->getOne('Profile');