The don of the family is Emilio Barzini.
The story on the Kabam website is "Emilio Barzini was the closest ally to the Tattaglia Family. His hand was in every unlawful pie – narcotics, sports betting, prostitution, strong arming – and this hand stretched far. In New York it was Brooklyn to Queens to Staten Island. But it didn’t stop there. His interests reached as far as Las Vegas, Reno, Miami, Cuba, and even Sicily. He had supported the Tattaglia Family with money and influence since the start of the war. It was his ambition to supplant Don Corleone as the most powerful and respected Mafia leader in the country and to take over part of the Corleone empire. He was a man much like Don Corleone, but more modern, more sophisticated, more businesslike. Barzini had the confidence of the newer, younger, brasher leaders on their way up. He was a man of great personal force in a cold way, with none of Don Corleone’s warmth. He was known by some to be the most “respected” man in the group."