Johnny Tattaglia was Don Phillip Tattaglia's eldest son and the Underboss of the Tattaglia's businesses. He took a much more active role in the running of his father's business than his younger brother Bruno, who spent most of his time running the The Luna Bar in Midtown.
After the attempted hit on Vito Corleone, he was a marked man, along with Virgil Sollozzo, Phillip Tattaglia and Bruno Tattaglia. The Corleones had planned to send Luca Brasi after him, but Luca had already been assasinated by Sollozzo and Bruno before the hit.To weaken his enemy's defences, Johnny planned a vicious and bloody strike that would cripple the Corleone family, after his own Family had nearly been destroyed by attacks from caporegime Salvatore Tessio in Brooklyn, who had arranged the assasinations of Mikey Saleri, Donnie Marinelli, Tony Bianchi and Freddie Nobile. Johnny's brother Bruno had also been killed shortly before, dealing a personal blow to the Family. Ultimately, Johnny was unable to act as he was killed in a fire caused by Corleone family enforcer Aldo Trapani. Johnny's death was the final nail in the coffin for the Tattaglias, and they were forced to seek the support of Emilio Barzini to keep them afloat.