Pastore played mobsters in the orbit of John Gotti in the HBO movie "Gotti" (1996) and in the NBC miniseries "Witness to the Mob" (1998), the Sammy Gravano story. He turned up in episodes of "New York Undercover" (Fox) and "Dellaventura" (CBS) and appeared four times on NBC's "Law & Order", not to mention his role in the CBS miniseries "Mario Puzo's The Last Don" (1997). All this was a prelude to the project that would really put him over, HBO's acclaimed "The Sopranos" (1999- ). His part as 'Big Pussy' Bompensiero, Tony Soprano's right-hand man and confidant, enabled him to move from his $300-a-month Bronx apartment to one in the borough's picturesque City Island, and he became an icon among character actors specializing in playing "goombah" roles. The first season even ended with his character missing in action and feared dead, though he turned up alive and well for its second season--though his character's ultimate fate would reverberate through the series' entire run. With the exposure provided by "The Sopranos," suddenly Pastore was everywhere, portraying a funny gangster in "Mickey Blue Eyes" (in which everybody seemed supplied by Central Casting, Gangster Division), playing a larger part in the routine melodrama "Under Hellgate Bridge" (with "Sopranos" co-star Dominic Chianese) and acting in Norman Jewison's "The Hurricane" and TNT's A Slight Case of Murder" (all 1999), as well as appearing in a high-profile Pepsi campaign, unwisely trying to pass off "garbage" as Pepsi to the little girl (Hallie Eisenberg) who channels Joe Pesci, Marlon Brando and others.
In 2002, Pastore was cast as Tony in the summer comedy "Servicing Sara," a story about a process server who is convinced by a New York wife to serve her husband divorce papers, which isn't as easy as it should be. The actor continued to play thugs, knucklebreakers and tough guys in a string of character turns, including a year-long stint as Arthur "Rack 'Em Up" Ross on the enduring ABC daytime drama "One Life to Live" (2003-2004), and as the finny wiseguy Luca in DreamWorks' CGI-animated film "Shark Tale" (2004), and he racked up many TV credits, including recurring roles on "Son of the Beach," "Queens Supreme" and "The Practice." In 2005 his personal life made the headlines when Pastore pleaded guilty in New York City to misdemeanor attempted assault of his girlfriend.