Fredric March

Marcus Superbus - Prefect of Rome

Elissa Landi

Mercia

Claudette Colbert

Empress Poppaea

Charles Laughton

Emperor Nero Claudius Caesar

Ian Keith

Tigellinus

Arthur Hohl

Titus

Harry Beresford

Favius Fontelas

Tommy Conlon

Stephan

Ferdinand Gottschalk

Glabrio

Vivian Tobin

Dacia

William V. Mong

Licinius

Joyzelle Joyner

Ancaria

Richard Alexander

Viturius

Nat Pendleton

Strabo

Clarence Burton

Servillius

Harold Healy

Tybul

Robert Seiter

Philodemus

Charles Middleton

Tyros

Henry Brandon

Colosseum Spectator (uncredited)

John Carradine

Christian Martyr / Gladiator Leader / Voice in Coliseum Mob (uncredited)

Dave O'Brien

Christian on Stairway (uncredited)

Sally Rand

Crocodiles' Victim (uncredited)

Arthur Shields

Chaplain Costello (1944 Re-Release Prologue) (uncredited)

Tom Tully

Hoboken (1944 Re-Release Prologue) (uncredited)

Lionel Belmore

Bettor of 300 Silver

Ynez Seabury

Little Girl