The restaurant was most likely a shared turf by the Leone's and the Forelli family. In GTA San Andreas in 1992, Salvatore Leone, don of Leone family ordered ally, Carl Johnson to kill a high ranking Forelli gang member in the mission Saint Mark's Bistro.
By 1998, the front is owned by the Leone's as they are the only Mafia family controlling the areas surrounding Saint Mark's in GTA Liberty City Stories. The Forelli's main base is the Little Italy district in Fort Staunton.
In 2001, where GTA III takes place, the Forelli's are weakened considerably and instead known as the Forelli brothers. During the same time, their only known front is Marco's Bistro, noted as Mike "Lips" Forelli (the speculated don) is seen there.
The restaurant's slogan in Grand Theft Auto III is "Eat till you explode!", an ironic reference to Mike Forelli's death and a GTA III mission when you take a car, go to a bomb shop to install an ignition bomb and see the owner being killed by the car explosion.