In the 1920s and 1930s Jewish gangsters united to form large-scale businesses that dealt in prostitution, extortion, drugs and bootlegging. They also went into the assassination business to ensure that they remained in power throughout the major cities of the United States. Some Jewish gangsters united with their Italian contemporaries and functioned under Mafia rules. By the Second World War, battles over turf and arrests by the Federal Bureau of Investigation had convinced many of these people to go legitimate and they moved to Las Vegas and went into the entertainment business. 

What is interesting is that some of the Jewish mobsters, such as David Berman, fought valiantly during the war or supported the Allied effort in other ways such as protecting the docks and ports where they remained in power.

Meyer Lansky, Mob Accountant

Samuel Gompers, founder of AFL

John L. Lewis, Founder of CIO

Murder, Inc.

Samuel Red Levine

Moe Sedway

Bo Weimberg

Arnold Rothstein

Louis Buchalter

Meyer Lansky(born Meier Suchowlański;[2] July 4, 1902 – January 15, 1983), known as the "Mob's Accountant", was an American[3] major organizedcrime figure who, along with his associate Charles "Lucky" Luciano, was instrumental in the development of the National Crime Syndicate in the United States.[4]

The Five Families are the five major New York City organized crime families of the Italian American Mafia.

The term was first used in 1931, when Salvatore Maranzano formally organized the previously warring gangs into what are now known as the Bonanno, Colombo, Gambino, Genovese, and Lucchese crime families, each with demarcated territory, organizationally structured in a now-familiar hierarchy, and having them reporting up to the same overarching governing entity. Initially Maranzano intended each family's boss to report to him as the capo di tutti capi (boss of all bosses), but this led to his assassination and by September the role was replaced by The Commission, which continues to govern American Mafia activities in the United States and Canada.