Dermot Mulroney: Dermot Mulroney. Actor: My Best Friend's Wedding. Dermot Mulroney was born in Alexandria, Virginia, to Ellen and Michael Mulroney, a law professor at Villanova. Since being discovered at Northwestern University by a Hollywood talent agent 28 years ago, Mulroney has been seen in over 70 films. Mulroney is a classically trained cellist who began playing in Alexandria, Virginia's public school system when he was 7 years old. He plays with...