His dad ran the Florida mob in conjunction with the American Crime Syndicate. In 1942, pops sent sonny boy down to Cuba to start up some casinos in Havana. After four years of preparing, designing, and building the first of what was to become a long string of gambling houses, Lucky Luciano arrived with a cavalcade of Syndicate associates.
The Havana conference of 1946 was portrayed in The Godfather, but the outcome was a bit different from Santos' perspective. He was forced to split his profits. This was a tremendous blow to the Trafficante family income. They had spent their own money to build and decorate the facilities in Havana, but now the profits were being sucked off by the big wigs up north.
But the Trafficante clan was beholden to Lucky Luciano. Everyone was. He controlled the entire North American continent, after all. Santos gritted his teeth and bore the brunt of the finacial wrath. Things chugged along pretty well for him until Fidel Castro came to power in 1952.
Castro threw Santos in jail and took over all the mafia's casinos and opperations on the island. Santos remained there until Castro called him into his office in 1958. No one knows what the two talked about, but by the end of the week, Santos was sent back to the US.
During the early sixties, Santos became part of the CIA's underground mafia opperations, the main goal of which was to assasinate Castro. There were a number of attempts on Castro's life, but they continually failed. Santos was placed high on totem pole of these operations, so when the third failed attempt was reported, the CIA began to suspect that Santos was a double agent. It was later revealed that he had diluted some of the poisons placed in Castro's drinking water.
In 1965, it became even more appherent that Santos was working both sides when a commrade in arms mentioned under oath that in 1962, Santos had told him "Kennedy's gonna get whacked."
Of course, that information could easily have come from the CIA, Castro, or the mafia itself.