He is introduced as the ostensibly pragmatic, calculating underboss of the New York Lupertazzi crime family as well as an ally of the Soprano crime family. However, following the death of Carmine Lupertazzi Sr. He serves as one of the main antagonists of Season 5. However, by Johnny had risen to become Carmine's right-hand man and underboss. A longtime chain-smoker, Johnny picked up tobacco around , and despite several promises to Ginny about quitting, continued consuming until his final days.
As seen in " Mr. John Sacrimoni Request John's mother died at an unknown date, though John's children still seem to remember her, while his father is still living, but appears to be on an age-related cognitive decline.
Hoping to resolve the issue in a discreet manner through which he can reduce Junior's fine without actually appearing to be involved, Tony requests Johnny Sack's help, meeting with him at a restaurant in Manhattan where he is celeberating his and Carmela Soprano 's anniversary; he explains that it should look as though Hesh approached Johnny in person to represent him at their sitdown, and that the final concession shouldn't be insulting to his uncle.
Gleefully exclaiming that he is "still running things", Johnny agrees and lets Tony rejoin Carmela for dinner, later sending over some celebratory cake for their table. When a meeting with Junior is later held in front of Satriale's , Johnny first plays into his ego by seriously stating that he would never tell him how to run his own family, but since Hesh also has contacts in New York, somebody needs to step in for him.
Tony pretends to be offended by Hesh "having [his] dirty laundry in public" and says he should have come to him first which he actually did , but he rebukes this, exclaiming that it would have been insulting to Junior if he went to Tony right after he announced his demands to Hesh.
