Vito was a low-level soldier in the Soprano/DiMeo crime family until his uncle Richie Aprile got out of jail in season 2. Once out, Richie re-assumed his old position of capo, and inducted Vito, at that point mostly involved in running Spatafore Construction, into the reinstated Aprile crew.
Slowly, but surely, Vito has risen to the rank of capo of the Aprile crew. As time passed the Apriles suffered heavy losses. First, Richie Aprile, its original captain was murdered by his fiancee Janice Soprano. Then, his successor, Gigi Cestone died of natural causes. Vito himself was hired to take out Jackie Aprile, Jr., the late Jackie Aprile, Sr.'s son. Later on, Donny K, an associate under new capo Ralph Cifaretto, was beaten to the point of nerve damage by Johnny Sack, then-underboss to New York's Carmine Lupertazzi. And finally, capo Ralph was murdered by Tony Soprano in a violent rage. Subsequently, Vito became the capo of the Aprile crew.
However, the curse of the Apriles may soon catch up with Vito. In season 5, it was revealed that Vito is a homosexual/bisexual, a strict no-no in the Mafia. Perhaps more important is the fact that Vito was spreading dissent at the end of season 5, as the Tony Blundetto crisis with New York came to a head.