Joseph Fischetti, also known as a "Chicago gangster," but better known for his activities in Miami, especially in connection with the Fontainbleu Hotel, was one of Sinatra's closest friends in the 1940s. FBI surveillance of Fischetti shows that he and Sinatra kept in weekly telephone contact for an extended period. They met in person several times in New York and Miami.

Sinatra was Joseph Fischetti's houseguest in Miami in February 1947 when they travelled to Havana in the company of Joseph's brother, Rocco, who was in charge of Chicago gambling and was a notorious woman-beater. On this infamous trip Sinatra met with Charles "Lucky" Luciano. Rumours about this meeting dogged Sinatra for the rest of his life.

Sinatra and Joseph Fischetti remained friends for years. Sinatra performed many times at the Fontainbleu Hotel in Miami. Fischetti was deeply involved with this hotel. As early as May 1947 Fischetti had bragged to an FBI informant about his "financial interest" in Frank Sinatra. Fischetti worked as a sort of agent for Sinatra in Miami and Chicago and got him several bookings in the early 1950s when Sinatra’s career was nearly dead.

Fischetti's financial interest nearly came to light in 1963 when the IRS investigated the so-called "Fontainbleu Complex." This investigation revealed that Sinatra performed "without charge" at the Fontainbleu and that Joseph Fischetti, who was being paid more than $1,000 per month to arrange Sinatra's performances, gave him expensive pieces of jewellery instead of cash. This story came to light again during Nevada Gaming Commission hearings in 1981. Again the charges were never proved.