LaVallee started his National Hockey League career with the Calgary Flames in 1980. He also played for the Los Angeles Kings, Pittsburgh Penguins, and St. Louis Blues. He left the NHL after the 1987 season.
He played in a total of 366 NHL games, scoring 110 goals and 125 assists.
He played 8 seasons in various European leagues. LaVallee played with Innsbruck EV in Austria from 1987–88 until midway through 1989–90. He then played for SC Bern for the remainder of that season. In 1990–91 He moved to Italy playing for HC Milano. In 1991–92 he played for a different team in Milan. In 1992–93 He joined the Ayr Raiders of the BHL. Later that season he moved to Ratingen EC in Germany. He moved a third time in 1992–93 this time to Ajoie in the Swiss National League A. In 1993–94 he went back to Germany with Düsseldorfer EG. He moved with the team in 1994–95 to the newly created DEL. In 1995–96 he started the season playing for the DEL's EC Hannover before returning to Switzerland and playing for HC Davos in the National League A. After 1995–96 he decided to retire from hockey.