The movie presents Victor Mature as Demetrius, a Christian slave made to fight in the Roman arena as a gladiator, and Susan Hayward as Messalina, a reprobate who is the wife of Claudius, the uncle of the depraved emperor Caligula.

The cast also features Ernest Borgnine, William Marshall, Michael Rennie, Jay Robinson as Caligula, Debra Paget, Anne Bancroft in one of her earlier roles, and Julie Newmar as a briefly seen dancing entertainer.

After his friends Marcellus and Diana are executed for heresy and treason, Demetrius makes it his mission to hide the Robe of Christ.

One day, while with his beloved, Lucia (Debra Paget), he is arrested for assaulting a Roman centurion and sentenced to the arena.

The emperor, Caligula, appoints him bodyguard of Messalina (Susan Hayward), unfaithful wife of Claudius (Barry Jones).

Bosley Crowther of The New York Times wrote that "we've got to hand it to Producer Frank Ross and Philip Dunne, the writer who put this one together out of whole cloth instead of 'The Robe' ... they have millinered this saga along straight Cecil B. Devotional lines, which means stitching on equal cuttings of spectacle, action, sex and reverence.

"[8] Variety called the film "a worthy successor" to The Robe, "beautifully fashioned with all the basics of good drama and action that can play, and quite often do, against any setting, period or modern.

"[9] Edwin Schallert of the Los Angeles Times wrote, "As long as Mature is merely bluffing at being a gladiator, and trying at the same time to remain true to the principles of Christianity, the drama of the picture limps along ... Once Mature suddenly goes on a rampage as a fighter in the arena, 'Demetrius' takes on new life.

"[10] Richard L. Coe of The Washington Post stated, "Because there is less of the religious aspect of its Lloyd C. Douglas predecessor, and much more of the man-versus-lions-versus-men-versus-women-versus-vino of the early Cecil B. DeMille school herein, I suspect that, moviewise at least, 'Demetrius and the Gladiators' is a more enjoyable, less stuffy entertainment.

"[12] The Monthly Film Bulletin wrote, "This sequel to The Robe seems much less inhibited by religious awe than its predecessor.

Twice it turns back reverently to The Robe (in flashback) as to a chastening altar, but happily soon regains its own noisy bounce in describing suggestive doings in dirty ancient Rome.