- "I've probably forgotten more about this business than you'll ever learn."
- — Leo Galante
Leo is consigliere to Frank Vinci and the mastermind behind the Vinci Crime Family, the most successful criminal organization in Empire Bay's history. Upon their arrival from Sicily in 1908, the pair set up the family with Leo strategizing and Frank provided the muscle. In the early 1920s the pair took control of the Southport docks, which made for easy smuggling of alcohol during Prohibition.
Leo's passion lies in sports, especially boxing and horse racing. He used to fight in bare knuckle matches before becoming a prize-fighter. Later Leo ran the city's biggest bookmaking operation for 20 years. In 1933 he conspired with Carlo Falcone to assassinate Tomaso Moretti, bringing an end to the Vinci-Moretti War and the Moretti crime family.  Leo currently resides in a large mansion in Highbrook, Empire Bay.
He was arrested for bookmaking and fixing fights in 1943 and sentenced to five years in Hartmann Federal Penitentiary. Due to his status and connections, Leo continued to live an entitled lifestyle while in prison. His cell was a suite, complete with cooking facilities, and he was able to do as he pleases, which included the ability to instruct the guards to do favors for him. It is here that Leo first met Vito Scaletta, after a confrontation between Vito and Brian O'Neill in the prison yard.
Leo was so impressed with Vito's fighting ability that he accepted him into his circle as a fighter along with his bodyguard, Pepé Costa. Over time he became a mentor to young Vito, teaching him about boxing and how The Mafia operates. Leo invited Vito to stay in his cell after he killed Brian O'Neill, and the two became close friends. Once Leo was released from prison in 1948, he influenced the parole board to release Vito Scaletta in 1951, taking four years off of his sentence.
After his release Leo continued to serve as Consigliere to Frank Vinci. In 1951 he made good on his promise to Vito Scaletta by recommending him when the books were opened to accept new made men. He would have preferred bringing Vito into the Vinci family, but because of his relationship with Joe Barbaro, it was decided to place him with the Falcone Crime Family instead.
In July 1951, the Vinci family was planning to make a move on Falcone. They were aware of his involvement in the drug trade, something Frank Vinci was strongly against, and saw it as an opportunity. However, Falcone decided to make a preemptive move by sending Henry Tomasino to kill Leo to both weaken the Vincis and send a message. Due to his close friendship with Leo, Vito Scaletta decides to warn him of the impending hit. Knowing that Carlo Falcone is after him, Leo decides to leave Empire Bay to retire down south.
Leo returned from his exile in the hopes of stopping the bloodshed between the Empire Bay Triads and the Mafia families caused by Vito and Joe after the Triads killed Henry Tomasino, who was working as a federal informant. It was decided that killing Carlo Falcone would be advantageous to both groups and that Vito should be the one to do it. Together with Mr. Chu, leader of the Triads, Leo informs Vito of his present situation and offers him an ultimatum; either kill Carlo Falcone or be killed himself.
Once Falcone is dead, Leo meets with Vito outside the Zavesky Observatory to celebrate. Vito is placed in the car with Leo while Joe is placed in another. As the two are driven off in different directions, Leo informs Vito that Joe wasn't part of their deal. As a result of this deal negotiated with the Triads to spare Vito's life, Vito is sent to New Bordeaux to work for the Marcano Crime Family.
Correspondence with Vito
Leo has received coded postcards mailed from Vito Scaletta in New Bordeaux, dated March 7 through June 14, 1967. They are addressed to Fowler & Webb Fine Tailors, Little Italy 25, Empire Bay 03491. They describe recent events in Vito's life and the Marcano Crime Family.
Meeting with Lincoln Clay
In the aftermath of Lincoln Clay's crusade against the Marcano Crime Family and the killing of Sal Marcano, Leo arrives in New Bordeaux to speak with Lincoln, revealing that The Commission is worried that he will be coming after them next. But Leo shows understanding behind Lincoln's crusade and urges him to end it and move on. The pair are left on good terms, and Leo says that he may run things as he sees fit, and as long as they still get their 20%, as Sal once had, there will be no problem. Leo then gets in his limo and departs.
- Genevieve Ferrari (mother)
- Michele Galante Sr. (father)
- Michele Galante Jr. (brother)
- Nunzio Galante (brother)
- His favorite game seems to be chess, as mentioned by other prisoners in Hartmann Federal Penitentiary.
- The ending cutscene of Time Well Spent, including Leo cooking and discussing how the Mafia works, is reminiscent of a scene in the popular gangster movie Goodfellas.
- Leo mentions in A Friend of Ours that his wife is deceased, but no other information is revealed about her.
- Despite Vito's respect for Leo in Mafia II, Vito's views about him have changed in the 17 years since his exile to New Bordeaux. During interactions with Lincoln, Vito refers to Leo as a "cocksucker" and appears to hold him in the same regard as former foes like Alberto Clemente and Derek Pappalardo.
- If Vito is killed in Mafia III, he mentions Leo along with Alberto Clemente and Derek Pappalardo before he dies, referring to them as "cocksuckers".