Eugene Pontecorvo was introduced on the show as an associate in the DiMeo Crime Family in the episode Proshai, Livushka. Eugene subsequently becomes a made man in the following episode Fortunate Son along with Christopher Moltisanti. Like Vito Spatafore and Benny Fazio he is introduced as a small character whose role slowly increases throughout the series. His first act on the show is seen in Proshai, Livushka when he and Gigi beat up on a garbage sanitation man for threatening to rat out Ralph Cifaretto. Eugene Pontecorvo also appears in a flashback to 1995 in the episode …To Save Us All From Satan's Power as a body guard along with Gigi Cestone of Junior. He, along with Vito Spatafore and Donny K., found Gigi Cestone dead on the toilet in the Aprile Crew hangout after suffering a constipation induced heart attack.
Eugene's bad side resurfaces as he is sent to intimidate a juror who is on Junior's RICO trial. He and another associate tell him "We know you'll make the right decision."
Although mild-mannered, Eugene has a tendency to lose his temper, similar to Ralph Cifaretto. In the episode Unidentified Black Males, while he and Little Paulie Germani are trading insults with each other, Little Paulie goes too far in Eugene's mind when he suggests through innuendo that Eugene is a homosexual. Eugene responds by smashing a glass bottle over Little Paulie's head.
In season 6, it is revealed Eugene Pontecorvo has been an informant for the F.B.I., though it is unclear for how long. He states to his friends that, "The only thing I ever found in the street was my first wife." This shows that he has had at least one failed marriage. It also shows that his wife is financially unstable and cannot support herself. He also inherits 2 million dollars from his deceased aunt. He begins developing serious stress with his home life due to his wife pushing him to talk Tony into their retiring to Florida with the money and also his son's incessant drug-use. Eugene has a talk with Tony about him and his family moving to Florida permanently. Tony says he'll consider it, but he states Eugene took an oath indicating it's highly unlikely he'll approve. Christopher Moltisanti assigns Eugene the task of taking out a guy named Teddy Spirodakis in Boston, Massachusetts who owed Christopher money and failed to pay him. Eugene is reluctant to do so but has to being that Chris is a Capo. Chris assures Eugene he will put in a good word for him to Tony as an appreciation for doing the hit. Eugene drives to Boston and finds Teddy eating dinner at a fast food restaurant and shoots him repeatedly in the head. Eugene walks out calmly. This will be Eugene's last performed hit. After Raymond Curto dies of a massive stroke while giving potentially damaging information to Agent Robyn Sanseverino, the F.B.I. informs Eugene they also refuse his notion to move to Florida, for they need him in Jersey too to help build a case against Tony. Silvio had also informed him an earlier scene that Tony denied his request to move. With Tony and the Feds both hindering Eugene's chance to escape the mafia life and his stress caused by his unstable home life, Eugene takes the only way out he knows: He hangs himself in his basement. With the "disappearance" of Ralphie and the whacking of Vito, Eugene was second in command in The Aprile Crew, so he would have presumably made Capo after Vito's death; however, he would have also met the same fate that Big Pussy and Adriana La Cerva met if his identity as an informant had been discovered.