Born June 20, 1915 Bensonhurst, Brooklyn. Assassinated December 16, 1985 in Manhattan by John Gotti and associates.

Castellano is best known as the last godfather of the Gambino crime family before John Gotti took control in 1985. As godfather, "Big Paul" Castellano garnered resentment among many rank and file mobsters by living in a remote, lavish mansion on Staten Island and by exacting exceptionally large tributes from his men. Castellano's thirst for profits also motivated him to tacitly allow more drug trafficking in the Gambino outfit, despite a prior agreement among the five families of La Cosa Nostra that, due to the temptation to inform under the threat of increasingly harsh prison sentences, any gangster caught dealing drugs would be executed by their own mob family.

Although he was a meatcutter by trade, "Big Paul" had racketeering in his blood, and began by helping his father's illegal lottery business at an early age. Castellano's first stint behind bars was a three month sentence at the Hartford County Jail for armed robbery when he was 19 years old. Soon after, he married a relative of his cousin, future godfather Carlo Gambino, adding yet another familial link to the somewhat inbred mix of relationships between the Castellanos and the Gambinos.

Don Carlo was an undisputed genius at running the Gambino family, so his death in 1976 left some big shoes to fill. The normal line of succession was broken because respected Gambino underboss Aniello "Neil" Dellacroce was incarcerated at the time, so the dying godfather named Castellano as the new boss of bosses. Neil Dellacroce and Castellano came to a peaceful agreement that would allow Castellano to control the Gambino family.

Castellano was a rather aloof and inaccessible leader, acting more like a banker than a mafia godfather. As the head of a large, successful, and legitimate meatcutting enterprise, he saw the Gambino family as just another business to run, which irritated his underlings to no end.

His problems with impotence from diabetes contributed to his divorce from Nina Manno and an affair with his Colombian housekeeper, Gloria Olarte. Olarte unwittingly allowed the FBI to bug the Castellano mansion, which was built to resemble the White House. Big Paul's dalliances further fueled the animosity of the Gambino soldiers, but Dellacroce urged them to toe the line and respect Castellano regardless.

Dellacroce was the glue that held Castellano's leadership together, so when Dellacroce died from brain cancer on December 2, 1985, Castellano quickly lost any support he previously had. Even though Castellano was one of the key defendants in the FBI's Commission Case filed earlier that year and was urged by his attorney to keep a low profile, Gambino family soldiers took it personally when Castellano didn't show up to pay his respects at Dellacroce's funeral. Dellacroce's top solider, John Gotti, took that snub as the final insult and decided to execute Castellano and his dim-witted underboss Tommy Bilotti and assume control of the family.