After Sinatra’s marriage to Nancy Barbato, Moretti (a.k.a. Willie Moore) took an interest in the young singer’s career. He arranged several singing engagements for Sinatra, giving his career a large boost. Moretti also set an example for other mobsters who would later befriend Sinatra. Sinatra several times denied that Moretti helped his career. Columnist Lee Mortimer’s allegations concerning Moretti led to Sinatra assaulting Mortimer. Sinatra’s private testimony to the Kefauver Committee, on March 1, 1951, tells the true story, "Well, Moore, I mean Moretti, made some band dates for me when I first got started…." In 1948 Moretti told undercover FBI agents that he had an "association" with Sinatra. Later that year an informant told the FBI that both Sinatra and comedian Lou Costello "kicked in" to Moretti. In 1949, when Sinatra separated from his wife and was seen in public with Ava Gardner, Moretti sent him a telegram urging him to return to his wife.

Moretti testified openly, maybe too openly, to the Kefauver Committee, admitting that he was a gambler.

Ten months later he was gunned down in Joe’s ElbowRoom in Cliffside Park, N.J. Later, when Mario Puzo’s book, "The Godfather", came out it was widely rumored that one of the characters was based on Sinatra and that Don Corleone was partly based on Willie Moretti.

Tommy Dorsey always denied that he had been threatened in order to release Sinatra from his long-term contract; it is fairly certain that movie mogul Harry Cohn never found a horse’s head in his bed. But Sinatra did sing at the wedding of Moretti’s daughter in 1948, and he clearly had a great deal of affection for his neighbour and benefactor, Willie Moretti. Moretti, in return, took a great interest in Sinatra’s career and helped him wherever he could.