Phelps becomes history's most medaled Olympian
Phelps won his 19th career medal overall, eclipsing the 18-medal haul of Soviet gymnast Larisa Latynina from 1956 to 1964, when he anchored the team home with a huge, 3.07 second lead in a fitting finish.
The French team took silver, with the Chinese winning bronze.
France was represented by Amaury Leveaux, Gregory Mallet, Clement Lefert and Yannick Agnel, three of the team that won the 4x100 meters freestyle relay Monday.
China, meanwhile, took third with Hao Yun, Li Yunqi, Jiang Haiqi and Sun Yang.
Phelps was handed a virtually unassailable lead by teammates Ryan Lochte, Conor Dwyer and Ricky Berens.
Of Phelps' collection, 15 medals are gold, eight of which he won in Beijing, setting a separate record there four years ago.
He took two more bronze in China, before making a low-key start in London.
Phelps was edged out into fourth in Saturday's 400m individual medley, which was won by teammate Lochte.
He took silver with his team in Sunday's 4x100m freestyle relay that was won by the French, and equaled Latynina's record earlier Tuesday by finishing runnerup to Chad le Clos in the men's 200m butterfly.