Lew Ayres
— Dr. James Kildare
Lionel Barrymore
— Dr. Leonard Gillespie
Laraine Day
— Nurse Mary Lamont
Nat Pendleton
— Joe Wayman
Lana Turner
— Rosalie Lewett
Samuel S. Hinds
— Dr. Stephen Kildare
Lynne Carver
— Alice Raymond
Emma Dunn
— Mrs. Martha Kildare
Walter Kingsford
— Dr. Walter Carew
Alma Kruger
— Molly Byrd
Harlan Briggs
— James Galt
Henry Hunter
— Harry Galt
Marie Blake
— Sally
Phillip Terry
— Bates
Roger Converse
— Joiner
Don 'Red' Barry
— Collins
Reed Hadley
— Tom Crandell
Nell Craig
— Nurse "Nosey" Parker
George Offerman, Jr.
— Nick
Clinton Rosemond
— Conover
Johnny Walsh
— 'Red'
Dorothy Adams
— Jenny's Mother (uncredited)
Barbara Bedford
— Dr. Carew's Secretary (uncredited)
Margaret Bert
— Mrs. Benson - Tommy's Mother (uncredited)
George Chandler
— Elevator Operator (uncredited)
Cliff Clark
— Detective Flaherty (uncredited)
Elspeth Dudgeon
— Old Lady in Hall (uncredited)
George Guhl
— Policeman in Nick's Hospital Room (uncredited)
Robert Homans
— Hickman - Policeman Bringing Jenny (uncredited)
Horace McMahon
— Fog Horn - Taxi Driver (uncredited)