Marcus Vipsanius Agrippa rose through his close partnership with Octavian, the future emperor Augustus. During the civil wars after Julius Caesar's assassination he supplied military and organizational ability that helped Octavian defeat rival commanders. As consul in 37 BC he developed naval facilities in Campania and prepared a fleet for the struggle against Sextus Pompey, whose command of Sicily threatened Rome's supply routes.

Agrippa's fleet won the decisive battle of Naulochus in 36 BC, breaking Pompey's maritime power. He again directed crucial naval operations in the campaign against Mark Antony and Cleopatra. By capturing positions and disrupting their communications before Actium in 31 BC, he helped create the conditions for Octavian's victory. His work encompassed training, supply, engineering, and the preparation on which victory depended.

After the civil wars Agrippa became a principal administrator of the new regime. He served further consulships alongside Octavian and undertook extensive public works at Rome. As aedile in 33 BC he repaired water infrastructure and improved public services; later projects included baths and aqueducts. He built the original Pantheon, although the surviving structure is a later rebuilding. Its dedication retained his name, preserving a visible link between his building program and the imperial city.

His marriage to Augustus's daughter Julia in 21 BC made him central to the dynasty's succession plans. Their sons Gaius and Lucius were adopted by Augustus. Agrippa received exceptional authority, including tribunician power, and carried out important assignments in the eastern provinces as well as campaigns in the West. These responsibilities made him more than a subordinate general: he was a partner in maintaining the settlement created after Actium. He died in 12 BC, before Augustus, and received a public funeral. His military service, administration, and family position helped secure the emerging principate.