With the title of Caesar, he was sent by his father, the emperor Carus, to the army of the Rhine in 282. On his father's death in the summer of 283, Carinus became emperor in the West, his brother Numerian becoming emperor in the East. After a campaign on the Rhine, Carinus returned to Rome where, in September 284, he celebrated games in honour of Carus' victories in Persia the year before.

Near Verona in the spring of 285, Carinus defeated Aurelius Julianus, the governor of Venetia, who had proclaimed himself emperor. Shortly afterward Carinus was killed by his own troops during a battle against Diocletian (who had succeeded Numerian as emperor in the East) on the banks of the Margus River.