Maximus (Russell Crowe):
Great general, close friend to emperor Marcus Aurelius, almost like a son. When the emperor dies, Commodus, the new emperor, son of Marcus Aurelius, sends soldiers to kill him. Maximus escapes. Later, he becomes a slave, and then a Gladiator.
Maximus, with Lucilla and Gracchus plan the death of the evil emperor, to make Rome a republic, again.
Marcus Aurelius (Richard Harris):
Emperor of Rome. Father of Lucilla and Commodus, close friend to Maximus. Wishes to give the throne to Maximus at his death, so he (Maximus), will turn Rome into a Republic, again. Killed by Commodus when he finds out about this.
Commodus (Joaquin Phoenix):
Son of Marcus Aurelius. Kills him when Marcus decides Maximus will be the new emperor at his death. Tries to kill Maximus, as well. Brother of Lucilla, uncle of Lucius.
He re-opens the Colosseum and that's where he meets Maximus once again. He will fight Maximus there, too.
Lucilla (Connie Nielsen):
Sister of Commodus, daughter of Marcus Aurelius, mother of Lucius (future emperor). Helps Maximus escape from the slave quarters, plans with him and Gracchus the death of Commodus fearing for her son's life and future.
Juba (Djimon Hounsou):
Slave and Gladiator. Good friend of Maximus, helps fight when Maximus escapes from slave quarters.
Hagen (Ralph Moeller):
Good friend of Maximus, slave and Gladiator, like Juba, he fights when Maximus escapes from the slave quarters.
Proximo (Oliver Reed):
Buys Juba and Maximus in Egypt to make them become Gladiators. Also owns Haken. Marcus Aurelius freed him in the past when HE was a Gladiator, gives Maximus advice to win his (Maximus's) freedom at the Colosseum. Helps Maximus escape from the slave quarters.
Gracchus (Derek Jacobi):
Member of the Senate of Rome. Tries to buy Maximus. Helps in the plan of killing Commodus.
Lucius (Spencer Treat Clark)
Son of Lucilla, nephew of Commodus. Inheritor of the thorne.
John Shrapnel ... Gaius
Tomas Arana ... Quintus
David Hemmings (I) .... Cassius
Tommy Flanagan (I) .... Cicero
Sven-Ole Thorsen .... Tiger