Sanderson appeared in many science fiction films, as one of the mechanics and regulars of the diner in
The Rocketeer, who defies Nazi agents looking for the top secret rocket pack. As a single episode character, Deuce, in the television show
Babylon 5 later reprising the role in
Babylon 5: Thirdspace. Sanderson voiced Dr. Karl Rossum in
Batman: The Animated Series. Sanderson starred in the 1977 blacksploitation thriller
Fight for Your Life, which is banned in the United Kingdom. He played the key supporting role of timid, genius inventor J. F. Sebastian in Ridley Scott's 1982 sci-fi-noir film
Blade Runner. As a guest, he made appearances in many television shows, his credits include
The Pretender,
The X-Files,
Knight Rider,
Married... with Children,
Babylon 5,
ER,
Coach, and
Walker, Texas Ranger. He plays a key role in an audio dramatization of
Ursula K. Le Guin's
Vaster than Empires and More Slow in NPR's
2000X series. In 2001, Sanderson played the courageous bartender Dewey in the
TNT film
Crossfire Trail. Sanderson's fame peaked in a comic-relief role, as the soiled, societally-awkward, backwoodsman Larry in
Newhart from 1982 to 1990, famous for the absurd catchphrase, "Hi. I'm Larry. This is my brother Darryl. This is my other brother Darryl" – a reoccurring character until the end of the second season, when he and his brothers purchased the cafe next to the Stratford Inn. Sanderson had a minor role as the abusive and cruel junkyard dealer Ray in ''
Man's Best Friend''. He returned to television playing
E. B. Farnum in the
HBO television series
Deadwood from 2004 to 2006, later reprising the role in its
film continuation. In 2008, Sanderson joined the cast of
True Blood, playing Sheriff Bud Dearborne. He played Oldham, the resident interrogation expert of the
DHARMA Initiative in an episode of the fifth season of the ABC series
Lost. In May 2019, Sanderson released an autobiography about his career, ''Yes, I'm That Guy: The Rough-and-Tumble Life of a Character Actor
. Following the release of his book, Sanderson and Nick "Saucey" Katsouros released a six-episode limited-run podcast, Sanderson Says'', to discuss and expound on the autobiography. Sanderson announced his retirement from acting on his Facebook page on May 13, 2020. ==Personal life==