Jonathan 'Johnny Sack' Sacrimoni was the underboss (later boss) of the Lupertazzi crime family. Johnny Sack was the right-hand of Carmine Lupertazzi Sr. for many years before he took over as boss following a period of infighting, which led to the deaths of several key figures in Little Carmine's faction, including fellow Lupertazzi caporegime Rusty Millio, shylock Lorraine Calluzzo and Carmine Lupertazzi's former consigliere, Angelo Garepe. Johnny Sack had also been a close friend of Tony Soprano for many years.
History
Although it is unclear as to exactly when Johnny Sack first hooked up with the Lupertazzi crime family, in his allocution he admitted to at least a ten-year connection beginning January 1st, 1996. However, given his age and position in the family, and how it is mentioned that he worked under Carmine Lupertazzi for years, it is more likely that he spent many years working his way up the ladder. He was Carmine's underboss for many years, handling political payoffs and bid-rigging for the outfit.
He was happily married to his obese wife, Ginny, with whom he had two daughters, Allegra Sacrimoni and Catherine Sacrimoni, respectively).
Season 1
After finding out that Tony Soprano was the de facto boss of the DiMeo crime family, he attended the sit-down with Junior Soprano about taxing Hesh. He later acted as an intermediary between the DiMeo crime family (secretly run by Tony) and at least two of the New York mob families (possibly Mangano)