John Sacrimoni, also known as Johnny Sack, is a character from The Sopranos series.
He was the underboss of the Lupertazzi Family and second-in-command to Carmine Lupertazzi. In many ways, John was different from many of his friends, as he genuinely loved his wife, Ginny, unlike most Mafiosi. He generally favored pragmatism over needless chaos. John was also a close friend of Tony Soprano, despite promising not to meddle in Tony's affairs after moving to Jersey. John went out of his way to try and fix the bad blood between Tony and Ralph Cifaretto, caused by Ralph's violent murder of a stripper. He likely did this to prevent Ralph from being killed so New York could continue to profit from the esplanade, rather than out of any real concern for either man. Though Tony never stopped disliking Ralph, he did make him Capo following Gigi Cestone's death, which kept the situation from escalating.
John cultivated a friendship with an incarcerated Paulie Gualtieri, successfully manipulating him into feeding him information about Tony and his crew, which John used to demand profits from Tony's scams. After learning from Paulie about an insult Ralph made at the expense of Ginny's weight, John was furious. He assaulted Donny Kafranza, assuming Donny was laughing at Ralph's joke, and asked Carmine to authorize a hit on Ralph. However, Carmine refused and permitted Tony to have John killed after correctly concluding that John intended to go behind his back and have Ralph killed. After finding out that Ginny had been hiding treats and wasn't really trying with her diet, John assured her he didn't care about her weight and decided to cancel the hit on Ralph, allowing a relieved Tony to, in turn, cancel the hit on John.
When Tony and Carmine were having problems over the HUD settlements, John encouraged Tony to kill Carmine in an attempt to become the boss. While Tony considered going through with it, he decided against it when Carmine offered him a more favorable split. Carmine died soon later anyway, leading to disagreements between John and Carmine's son, Little Carmine Lupertazzi, over who would be his successor. These disagreements led to a war started by John when he had Phil and Billy Leotardo kill loan shark Lorraine Calluzo for siding with Little Carmine. Little Carmine's men, Rusty Millio and Angelo Garepe, then retaliated by contracting Tony's cousin, Tony Blundetto, to kill John's underling, Joey Peeps, leaving John furious.
When John confronted Tony over this, Tony responded by lying to his friend and giving his cousin a false alibi. When John later had Little Carmine's ally, Angelo, killed by Billy and Phil, Tony Blundetto was enraged due to his close friendship with Angelo and sought vengeance by killing Billy. When John coldly told Tony he wanted Blundetto brought to him with the implication that Phil would draw out Blundetto's suffering as much as possible, Tony knew he couldn't risk a war but would not tolerate his cousin being tortured, so he chose to put him out of his misery by taking it upon himself to kill Blundetto. A tentative reconciliation followed this between Tony and John. However, their reconciliation was interrupted when the FBI came to arrest John, due to his consiglieri, Jimmy Petrille being an informant.
While in jail, John ordered Phil, now acting boss of the family, to maintain a good relationship with Tony and sent Phil to ask Tony to take care of Rusty, who John feared would try to wrestle power away from him and install a puppet as the new leader of the family. Tony refused, saying he needed to set boundaries. When John was granted temporary release to attend his daughter Allegra's wedding, he took the opportunity to talk business with Tony and persuaded Tony to agree to the hit. When the time came for John to leave, he was reluctant, wanting to wait until his daughter left. John was then dragged away from his daughter's wedding and broke down in tears. While Phil and others saw this as a weakness, Tony defended John, saying, "all bets are off when it comes to daughters." While John refused to rat, he eventually agreed to a plea deal in the hopes it would leave Ginny with enough money to live comfortably, costing him the respect of his colleagues.
During his time in prison, John developed cancer and passed away. When Tony and other mobsters learned of this, they all seemed saddened by the news, except for Paulie, who decided to take the opportunity to brag about how he beat cancer and John couldn't.