He was born in Little Italy to Italian immigrants from Genoa, Liguria. In 1976,after completing a prison sentence for hijacking, Grillo was recruited by DeMeo into his crew. Grillo and DeMeo had known each other through work in the Mafia-connected Canarsie junkyards. Grillo soon became involved in the hijacking of truck cargoes to and from John F. Kennedy International Airport in Brooklyn. Associate Dominick Montiglio, who became a government witness in 1983, described how DeMeo once asked him to temporarily store 120 stolen Smith and Wesson handguns. Grillo and other DeMeo crew members had hijacked the guns, headed to law enforcement in Finland as they were being transported to the airport. Montiglio stored the weapons for one day and then turned them over to Grillo and DeMeo.