| Spencer Tracy | Henry Drummond |
| Fredric March | Matthew Harrison Brady |
| Gene Kelly | E. K. Hornbeck |
| Dick York | Bertram T. Cates |
| Donna Anderson | Rachel Brown |
| Harry Morgan | Judge Mel Coffey |
| Claude Akins | Rev. Jeremiah Brown |
| Elliott Reid | Prosecutor Tom Davenport |
| Paul Hartman | Bailiff Horace Meeker |
| Philip Coolidge | Mayor Jason Carter |
| Jimmy Boyd | Howard |
| Noah Beery Jr. | John Stebbins |
| Norman Fell | WGN Radio Technician |
| Gordon Polk | George Sillers |
| Hope Summers | Mrs. Krebs - Righteous Townswoman |
| Ray Teal | Jessie H. Dunlap |
| Renee Godfrey | Mrs. Stebbins |
| Florence Eldridge | Sarah Brady |
| Gail Bonney | Fundamentalist Woman (uncredited) |
| Jack Daly | Eskimo Pie Vendor in Courtroom (uncredited) |
| Richard Deacon | Juror / Court Gallery (uncredited) |
| Lester Dorr | Dr. John (uncredited) |
| Donald Elson | Bollinger (uncredited) |
| David Fresco | Threatening Spectator (uncredited) |
| Sam Harris | Courtroom Extra (uncredited) |
| Earle Hodgins | Dr. Britton's Tonic Spieler with Chimp (uncredited) |
| Wendell Holmes | Banker - Critic at City Meeting (uncredited) |
| Frank Mills | Courtroom Extra (uncredited) |
| Robert Osterloh | Sam - Deputy Arresting Cates (uncredited) |
| Stephen Paylow | Courtroom Extra (uncredited) |
| Bob Perry | Courtroom Reporter (uncredited) |
| 'Snub' Pollard | Courtroom Extra (uncredited) |
| Addison Richards | Reporter at Dinner Table (uncredited) |
| Harry Tenbrook | Courtroom Extra (uncredited) |
| Charles Wagenheim | Hotel Clerk (uncredited) |
| Justice Watson | Hillsboro Salesman (uncredited) |
| Will Wright | Bible Salesman (uncredited) |
