Phil used to be a human but gets turned into a werewolf in the episode "An American Werewolf In America. He is attacked by a werewolf named Matthew Thornton on his way to see a Christ Angel performance. Part of his face and his left arm get ripped off and he somehow contracts lycanthropy even though he does not seem to have been bitten.
Phil is put into Mark Lilly's class along with Matthew. He asks Matthew for his wedding ring back but Matthew has not passed it yet, implying that Matthew has eaten Phil's arm, even though after getting arrested by Francis Grimes. Phil gradually becomes more and more like a werewolf during sessions of the class.
At Mark's funeral (after Mark was urged by Leonard Powers to shoot himself for a magic performance at Open Mic Night), Phil, almost a full werewolf, gives a speech and is seen to have grown back a very thin left arm. He makes up with Matthew and gets his wedding ring back.
Phil is seen adapting to life as a werewolf in flash images during the end credits. One of the images shows that he has a wife, a son and a daughter. He previously mentioned that he has a 6-year old kid.