He was elected consul in 216 BC, at the recommendation of the Dictator, whose orders he had faithfully obeyed even when obliged to abandon Italian allies to their fate. His colleague-elect Lucius Postumius A.f. Albinus being killed in an ambush in Gaul on his way home, Marcus Claudius Marcellus was elected consul in his stead, to the protests of patricians who claimed that two plebeians could not serve as consuls. Marcellus thereupon resigned and Quintus Fabius Maximus was elected consul to serve out the year. In that year, Fabius Maximus and the Senate decided to induct volunteer slaves into the Roman armies and to have them serve in separate legions to win their freedom. Gracchus was appointed commander of the slave troops, and he rapidly became known as an effective general of volunteer slave troops, winning their loyalty and trust for his clemency when some broke and ran from the field. [Livy]. He was appointed proconsul in 214 BC, continuing to lead his slave and freedmen troops in central and southern Italy with mixed successes against Hannibal.
In 213 BC he was re-elected consul. He was removing his troops from their winter camp on the orders of the newly elected consuls (of 212 BC) when he and a small group of men were ambushed and killed, allegedly when they were caught bathing. According to Livy, Hannibal gave the dead general full funeral rites and had his ashes returned to Rome.