Bill Lexington is the father of Will Lexington.
He is first seen in the Season Three episode Is The Better Part Over when he shows up to see his son perform. However, he is unaware about his son's true sexuality and makes Will uncomfortable while they eat together in a diner. He later expressed disgust after Will came out in a press conference.
However, when Will's mother dies and Will attends her funeral, he finally comes to his son's defense when a man makes a derogatory comment toward the latter.