He was the close friend/brother-in-law of Rocky Balboa, the older brother of the late Adrian Pennino (who became Balboa's wife), and the uncle of Rocky Balboa, Jr. Pennino was also a hardcore alcoholic, had a cynical attitude, and usually gave out negative comments, much to the dislike of his brother-in-law. He lived with his brother-in-law Rocky Balboa. He owned a robot. From at least 1975 to 2006 he worked as a Meat packer in Philadelphia. In 1976 he counfronted a pregnant Adrian about what her lack of faith in Rocky was doing to her husband's career. This caused her to go into labor premature and caused him grief to no end. Drunk by 1981, he asked Rocky for an extra job to help the champ train. Before Rocky went to Russia, he signed over power of attorney to the family accountant who stole nearly all of the family's money. Despite his alcoholism, drunken outbursts, jealously towards Rocky, and his generally-negative attitude, he has always been a dedicated friend to Rocky, staying at his side through success, loss, rough patches in their friendship, and trips throughout the world. Paulie has been known to be a borish, drunken, jealous, angry, intolerant person. As Rocky would later refer to him as a "Jealous Lazy bum." He has been known to be negative about everything in his life and lashing out on everybody he can. He also has a tendancy to believe that friends owe him even if they already repayed him. Although despite all this he cares for his sister Adrian, and his friend/brother in law, Rocky. Even using his attitude against those that have wronged him and his friends, despite it only having him ignored insulted or even punched out by the person he opposes. Although his sayings are negative and insulting, he has always known to have some truth in them. For example, when Tommy Gunn challenged Rocky to a fight, it was Paulie that pointed out that if it wasn't for Rocky that Gunn wouldn't be a contender.
Paulie first appears in Rocky along with the rest of the recurring characters. It is already shown that he knows Rocky has a crush on his sister Adrian, and goes as far as throwing away a thanks giving turkey so that Adrian wouldn't be too busy to go on a date with Rocky. He is shown to be working every day as an inspector at the meat packing plant and personaly gives Rocky some of the meat every morning. Every day he asks Rocky if his boss Gazzo has a job for him as an enforcer, but Rocky politely denies him. When Rocky is offered the shot at the title, Paulie asks if he (Rocky) already had sex yet which Rocky berates him for talking about his own sister in that way. During one of his visits to the meat packing plant Rocky, inspired by one of Paulie's freak outs about how it stinks in the meat plant hitting the cow carcass; decides to use his punching training on the carcass until the ribs broke. Paulie remarked that if Rocky does that to Apollo Creed that he would be hauled in for murder. He and Rocky have their first falling out on Christmas Eve, when Paulie hires a news crew to film rocky while he perfoms his punching training. It was then Rocky and Adrian discuss Paulie behind his back, when Paulie comes in the house and in a drunken rage berates Rocky about how he did everything for him and that Rocky never gave him anything in return. At the time he was wielding a baseball bat in an attempt to break Rocky's arms. When he remarked that he even gave Rocky Adrian, she snapped at him that she owed him nothing because she has been taking care of him for years and all he had to show for it was make her feel like a loser. Rocky restrains him while Adrian runs to her room crying, Paulie is also sobbing feeling guilty for what he did to them. While Rocky is training, Paulie reconciles with Rocky and asks him one small favor. During the match the favor is reveiled that Rocky places an advertisment of "Shamrock Meats" on his robe. After the fight, Paulie causes a ruckus with security distracting them so Adrian could get to Rocky in the ring.
- Paulie Pennino, Tony "Duke" Evers and Rocky Balboa were the only characters to appear in every single Rocky movie.
- Paulie hates getting gold watches as gifts.