Peter Mackenzie is an American actor. He co-starred in films Good Morning, Vietnam (1987), Torch Song Trilogy (1988), Lorenzo’s Oil (1992) and Trumbo (2015). He is also known for his television roles on Herman’s Head (1991–1994), ER (2002), Gilmore Girls (2006), Grey’s Anatomy (2009), How I Met Your Mother (2011) and Black-ish (2014–).