- "I've probably forgotten more about this business than you'll ever learn."
- — Leo Galante
Leone is an astute man with gray hair but should not be underestimated, despite his age. He is Sicilian-born, and has earned the nickname "The Lion". He previously spent some years behind bars in Sicily for murder and perjury, among other things. Leo arrived in Empire Bay in 1908, and built the Vinci syndicate alongside Frank Vinci by controlling the Southport docks in the 1920s, facilitating Prohibition alcohol smuggling. Leo currently resides in a palatial estate in the hills of Highbrook. Leo's known associates include Pepé Costa and Federico "Fat Derek" Pappalardo. As consigliere, he was important in mediating the negotiated peace that ended the Vinci-Moretti War.
At his introduction in 1945, he was serving a five-year sentence in prison for fixing fights, although despite this, he still continues to live the life of luxury due to his friendship with the prison Captain Terrence Stone. In prison, Leo was so impressed with Vito's raw fighting ability against a recently imprisoned Brian O'Neill, he accepted Vito into his circle as a sparring partner for his now bodyguard, Pepé. Vito soon proved to be the more capable earner and was put to work as an enforcer, killing Brian O'Neill helping settle Leo's affairs before his 1951 release. Once Leo was released from prison, he influenced the parole board to release Vito Scaletta four years ahead of sentence.
Shortly after his release, Leo continue to serve as consigliere and later convinced the Falcone crime family to "make" Vito into their family along with Joe Barbaro (Vito's best friend), he wanted to make Vito into the Vinci's but he didn't want to split Vito from Joe who had been working for the Falcone's for a while. Soon after Vito is made, Carlo Falcone decides to cover some illicit business by attempting to eliminate the Vinci's. Identifying Leone Galante as the brains of the Vinci operation, Falcone's first order in the vendetta is a hit on Leo. Eddie Scarpa tasks Henry Tomasino for the job when Vito declines. Viewing Leo as a father figure, Vito warns him of the incoming killer and attempts to sneak him out of his estate. Depending on the Player's actions, Leo is either caught by Henry and makes an undisclosed life-sparing deal with him, or escapes undetected via a bedsheet rope to the lawn. In either case, Vito then drives Leo to the train station in his pajamas, and Leo disappears from Empire Bay.
Leo returned from his exile in hopes of stopping the bloodshed between the Empire Bay Triads and the mafia families caused by Vito and Joe as revenge for the Triads killing Henry. It was decided that Don Falcone was to be eliminated because he poses as great a threat to them all, he then offered Vito a chance at redemption, by killing Falcone for starting the bloodshed in the first place. After Vito and Joe succeeded in killing Falcone, Leo awaited outside the Zavesky Observatory, along with Pepé and several Vinci soldiers. He then called for a celebration at the Garden of Eden. Leo and Pepé ride in the same car as Vito while Joe rides another car that would most likely take him to be killed elsewhere. Leo apologizes to Vito and claimed that Joe wasn't part of the deal.
- Genevieve Ferrari (mother)
- Michele Galante Sr. (father)
- Michele Galante Jr. (brother)
- Nunzio Galante (brother)
- His favorite color seems to be indigo, due to all his cars being indigo and even his tie being partly indigo.
- His favorite game seems to be chess, as said by prisoners in the jail that he and Vito shared.
- Frankie Potts' file on Leo claimed that he was unmarried, however this was untrue, he was indeed married however his wife had already passed away, so maybe they didn't know about this.
- Some of Leo's fighters inside the prison state that he was once a bare-knuckles fighter before becoming a famous prize-fighter.
- Even when he was in prison, he received special treatment from the guards and was well respected, such as getting a "suite" for a cell as Vito called it, being able to cook his own food and telling the guards to give Vito a day off.
- The "suite" in the prison as well as much of the cutscene, including Leo cooking pasta sauce and divulging previously unknown information to the "green member" of the family pays homage to the scene in "Goodfellas" when Paulie and Henry Hill are in prison together.
- Leo also has the nickname Uncle Leo because he is a mentor to many Mafia up-and-comers such as Vito.
- He runs illegal betting shops. You find out when two prisoners talk about him being put in jail for being the biggest bookie in the city.