A steady defenceman with some offensive abilities, Cavallini was selected by the Washington Capitals in the 1984 NHL Entry Draft. He entered the NHL after a season at Providence College where the Friars lost in the National Championchip to RPI and future NHL star Adam Oates. After playing parts of two seasons with the Capitals, he was traded to the St. Louis Blues where he would spend almost six seasons including his best campaign, the 1989–90 season. He played in the 1990 All-Star game and led the league in plus/minus rating that season. He then returned to the Capitals for a second tour during the 1992–93 NHL season in a trade that sent Kevin Miller to the Blues. Cavallini would once again be traded by the Capitals, this time to the Dallas Stars where he would play until his retirement a