Cavallini played a year at St. Mikes with the Buzzers, then headed to Bowling Green University on a scholarship. After two years, the Calgary Flames signed him as a free agent, and he immediately made an impact when he got to the team, scoring six goals in 27 games and providing energy and physical play.
After two partial seasons with the Flames, Cavallini was traded with Eddie Beers and Charlie Bourgeois to St. Louis for Joey Mullen, Terry Johnson, and Rik Wilson. He remained a Blues for more than years.
During those years (1986-92), the Blues made the playoffs each year and re-established the franchise as a competitive, winning one. Cavallini hit or came near the 20-goal mark for a while, though toward the end of his time in St. Louis his production dropped off. Midway through 1991-92 he was put on waivers and Quebec picked him up for a season and a half, and then Cavallini was sent to the IHL.
He continued to play, for three years, but rather than end his days in the minor pros he ventured to Europe where he continues to play year after year, enjoying a different culture and playing the game he loves, fewer games, fewer dollars, fewer pressures.