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), Criminal Minds (2005), Gilmore Girls (2006), Grey's Anatomy (2009), How I Met Your Mother (2011) and Black-ish (2014–2022).
In 2014, Mackenzie installed a small curbside book exchange on public land near his home which he called "The Tenn-Mann Library".
Popular in the neighborhood, it was cited for a local ordinance violation after an anonymous complaint.
Bullfighter: Part 1" at Benny and Develops an Órale Fixation" Kimble