Parisi was born to an Italian-American family in Newark, New Jersey, brother to Philly Parisi. He became a Soldier under Peter Paul Gualtieri but lost most of his loyalty to Tony Soprano when he ordered his brother's murder in 2000 for spreading rumors about him. He moved Patsy to a different area to keep him away from him, and Patsy took this seriously, and the FBI caught him leveling a gun at Tony through his window. He reconsidered and urinated in Tony's pool, and later quieted his hatred after talking with Gigi Cestone and Tony Soprano, the two men responsible for his brother's death.
In 2003, when Gualtieri was in prison, Christopher Moltisani became Caporegime, stepping over Parisi. They got into a fight and but when Gualtieri was released and made Underboss and Moltisani became permanent Capo, Parisi reconciled with him. Patsy also felt better when Tony killed his own cousin Tony Blundetto for the good of the family, which made him feel that his brother's death was also right.
One day, during the Soprano-Lupertazzi War, he was nearly killed alongside Silvio Dante by some of the Lupertazzi Family's gunmen, and Parisi fled into the woods after holding some of them off; Dante was wounded and put into a coma.