Tolkan is known for his role in the 1985 film Back to the Future as the strict, Hill Valley High School principal Gerald Strickland. He referred to Marty McFly, his father, and Biff Tannen derisively as "slackers". He reprised the role in the 1989 sequel Back to the Future Part II, where unnamed gang members made a drive-by assault on him in a bleak alternate present (then 1985). He also referred to these Criminals as "slackers" as he shot back. In 1990, he played the part of Mr. Strickland's grandfather Chief Marshal James Strickland in Back to the Future Part III. Tolkan would reprise his role as Strickland in addition to playing his character's ancestors and descendants in the 1991 animated series spin-off.