John Belushi as John "Bluto" Blutarsky: a drunken degenerate with his own style, in his seventh year of college, sporting a GPA of 0.0. He goes on to become a United States Senator.

Thomas Hulce as Lawrence "Pinto" Kroger: a shy but normal fellow, who becomes the editor of National Lampoon magazine. "Pinto" was screenwriter Chris Miller's nickname at his Dartmouth fraternity.

John Vernon as Dean Vernon Wormer: who wants to revoke the Deltas' charter and kick them off-campus.

Verna Bloom as Marion Wormer: the Dean's dipsomaniac wife.

Donald Sutherland as Professor Dave Jennings: a bored English professor who tries to turn his students on to left-wing politics and drug use.

Cesare Danova as Mayor Carmine DePasto: the shady local mayor with suggested mafia ties.