Mobster - Meyer Lansky

Meyer Lansky (born Meier Suchowljański), known as the "little Man" and the "Mob's Accountant", was a major organized crime figure who, along with his associate and friend Charles "Lucky" Luciano, was instrumental in the development of the National Crime Syndicate in the United States. Associated with the Jewish mob, Lansky developed a gambling empire that stretched across the world. He was said to own points (percentages) in casinos in Las Vegas, Cuba, The Bahamas and London. Although a member of the Jewish mob, Lansky undoubtedly had strong influence with the Italian-American Mafia and played a large role in the consolidation of the criminal underworld.

https://www.youtube.com/watch?v=89CH8AjV1oQ

I read he was unofficial consigliere at one point but I don't know if my information is accurate.

I would think he was that before that was even an actual title.