[2] In 42 BC he commanded a fleet of fifty ships in the Ionian Sea, and gained considerable success against the Second Triumvirate, completely defeating Gnaeus Domitius Calvinus on the day of the first battle of Philippi, as the latter attempted to sail out of Brundisium.

He was saluted imperator in consequence, and a record of this victory is preserved in the annexed coin, which represents a trophy placed upon the prow of a vessel.

After the Battle of Philippi in 42 BC, Ahenobarbus conducted the war independently of Sextus Pompey, and with a fleet of seventy ships and two legions plundered the coasts of the Ionian Sea.

With Gaius Sosius, Ahenobarbus fled from Rome to Antony at Ephesus, where he found Cleopatra with him, and endeavoured, in vain, to obtain her removal from the army.

Many of the soldiers, disgusted with the conduct of Antony, offered the command to Ahenobarbus, but he preferred to desert the party altogether, and defected to Octavian shortly before the Battle of Actium in 31 BC.

His wife was Aemilia Lepida and their son Lucius Domitius Ahenobarbus was married to Antonia Major, daughter of Mark Antony by Octavia the Younger.