He was chair of the philosophy department at University of California, Berkeley, a prominent educational reformer, and a key figure in the campus controversy over the 1950s loyalty oath.
California began to require University employees to sign a loyalty oath in the 1950s, and Tussman was a key organizer of protests.
Tussman moved to the philosophy department in 1952, leaving in 1955 when denied tenure for insufficient scholarly publication.
Over the next few years he taught at Syracuse and Wesleyan and completed his first book, Obligation and the Body Politic.
In 1965, Tussman founded the Tussman Experimental College Program (modeled on a program that Meiklejohn had created at Madison), which was offered to 150 students through their freshman and sophomore years and focused on great works written during times of great upheaval.