Main cast •
Lloyd Haynes as Mr. Pete Dixon, the protagonist, teaches 11th grade
American History in room 222 of Walt Whitman High School •
Denise Nicholas as Miss Liz McIntyre, guidance counselor at Whitman, dating Pete •
Michael Constantine as Mr. Seymour Kaufman, the principal of Whitman, preoccupied with his duties but dryly humorous •
Karen Valentine as Miss Alice Johnson, a student teacher learning from Pete
Recurring cast •
Jan Shutan as Bonnie, (8 episodes, 1969–1970) • Heshimu Cumbuka (as Heshimu) as Jason Allen, the "tough guy" of the class (89 episodes, 1969–1974) • David Jolliffe as Bernie, the school basketball star (83 episodes, 1969–1974) •
Judy Strangis as Helen Loomis, the "quiet kid" of the class (70 episodes, 1969–1974) • Howard Rice as Richie Lane, the "brainy" kid in the class (35 episodes, 1969–1971) •
Ta-Tanisha as Pam, the "popular girl" of the class (31 episodes, 1969–1972) •
Eric Laneuville as Larry (29 episodes, 1970–1974) •
Ivor Francis as Mr. Kenneth Dragen (16 episodes, 1969–1974) •
Patsy Garrett as Miss Hogarth (12 episodes, 1969–1973) • Robert Casper as Mr. Wisegarten, Mr Girard (12 episodes, 1969–1973) • Ty Henderson as Cleon (8 episodes, 1972–1974) •
Ramon Bieri as Mr. Gil Casey, vice principal (4 episodes, 1969–1970) •
Helen Kleeb as Miss Tandy (4 episodes, 1969–1971) •
Bruno Kirby as Herbie Considine (3 episodes, 1971–1973) •
Eve McVeagh as Madge Morano, Mrs Cates, PTA Member (2 episodes, 1969, 1971)
Guest stars Notable guest stars during the series five-season run include
Larry Linville,
Cindy Williams,
Chuck Norris,
Nancy Wilson,
DeForest Kelley,
Rob Reiner,
Richard Dreyfuss,
Burgess Meredith,
Kurt Russell,
Aretha Franklin,
Bernie Kopell,
Mako,
Don Most,
Angela Cartwright,
Ed Begley Jr.,
Dabney Coleman and
Mark Hamill. ==Episodes==