After being drafted in the first round by Calgary in 1981, he played 23 seasons in the NHL from 1982-2003. He remained with Calgary until 1994, when he signed as a free agent with St. Louis. He remained with the Blues until suffering a career-ending eye injury early in the 2003-04 season.
In 1989, he was selected as the playoff MVP (Conn Smythe Trophy) after his Flames team captured the Stanley Cup title. In 1999, he was awarded the NHL's defenseman of the year honors (Norris Trophy).