Octavia the Younger used family ties and household responsibilities to mediate between the men competing for power at Rome. After the death of her first husband, Gaius Claudius Marcellus, she married Mark Antony in 40 BC. The marriage helped seal his reconciliation with her brother Octavian at Brundisium. She had three children by Marcellus and two daughters by Antony, Antonia the Elder and Antonia the Younger.

Octavia lived with Antony in Athens and helped negotiate the Pact of Tarentum in 37 BC, renewing cooperation between him and Octavian. In 35 she traveled east with reinforcements and supplies, but Antony prevented her from joining him beyond Athens. Returning to Rome, she continued to maintain his household and assist his friends. Plutarch describes her resisting attempts to use her treatment as a pretext for civil war, although his account also reflects ancient ideals of the loyal Roman wife.

Antony divorced her in 32 BC. After his defeat and death in 30, Octavia helped raise surviving children from his other marriages and his relationship with Cleopatra alongside her own family. Her household thus connected former rivals to the emerging Augustan dynasty. Her son Marcellus died in 23, ending hopes attached to his marriage to Augustus's daughter Julia. Octavia died in 11 BC and received public funeral honors. Rome's Porticus Octaviae bore her name, while her daughters' descendants included the emperors Caligula, Claudius, and Nero.