 Joel McCreaWilliam Thomas Green Morton | William Thomas Green Morton |
 Betty FieldElizabeth Morton | Elizabeth Morton |
 Harry CareyProfessor John C. Warren | Professor John C. Warren |
 William DemarestEben Frost | Eben Frost |
 Louis Jean HeydtDr. Horace Wells | Dr. Horace Wells |
 Julius TannenDr. Charles T. Jackson | Dr. Charles T. Jackson |
 Edwin MaxwellVice-President of Medical Society | Vice-President of Medical Society |
 Porter HallPresident Franklin Pierce | President Franklin Pierce |
 Franklin PangbornDr. Heywood | Dr. Heywood |
 Grady SuttonHomer Quimby | Homer Quimby |
| DDonivee LeeBetty Morton | Betty Morton |
 Harry HaydenJudge Shipman | Judge Shipman |
 Torben MeyerDr. Dahlmeyer | Dr. Dahlmeyer |
 Victor PotelFirst Dental Patient | First Dental Patient |
 Thurston HallSenator Borland | Senator Borland |
 J. Farrell MacDonaldThe Priest | The Priest |
 Roscoe AtesMorton's Sign Painter - replaced by Hank Worden (uncredited) | Morton's Sign Painter - replaced by Hank Worden (uncredited) |
 Hank BellOnlooker (uncredited) | Onlooker (uncredited) |
 Franklyn FarnumMassachusetts Medical Society Man (uncredited) | Massachusetts Medical Society Man (uncredited) |
 Byron FoulgerMorton's Clinic Manager (uncredited) | Morton's Clinic Manager (uncredited) |
 Hank WordenMorton's Sign Painter - replaced Roscoe Ates (uncredited) | Morton's Sign Painter - replaced Roscoe Ates (uncredited) |
 Arthur HoytPresidential Secretary (uncredited) | Presidential Secretary (uncredited) |
