Derek Niles was the husband of Eleanor, father of Theresa, and the grandfather of David and Tom. Derek was a carpenter, and met Eleanor when he was in New York visiting friends.

Like his wife, Derek knew David's problems were spiritual, fighting Gerald and the doctors against giving David any medication. Derek liked to brag that David knew all the lyrics to "Aqualung" at a mere five years old.

Derek is the spirit twin of Theresa, David, and Tom's godfather, Jericho Cusick.