Together with his older brothers Mark Antony and Gaius Antonius, he spent his early years roaming through Rome in bad company.

He proposed an agrarian law in favor of the people and Caesar's veterans and took part in the operations at Mutina (43 BC).

In this year, he assisted Mark Antony's wife, Fulvia, who was anxious to recall her husband from Cleopatra's court, in the raising of an eight legion army to fight against Octavian's unpopular policies.

Later, observing the bitter feelings that had been evoked by the distribution of land among the veterans of Caesar, Antonius and Fulvia changed their attitude and stood forward as the defenders of those who had suffered from its operation.

Cicero, in his Philippics, actuated in great measure by personal animosity, gives a highly unfavorable view of his character.