The Windsor native played out his career in Edmonton with the Oilers, Arizona with the Coyotes, Buffalo with the Sabres, and Vancouver with the Canucks. In 661 games played in the NHL, Kassian collected 203 points, through 92 goals, and 111 assists.
Prior to the 2023-24 season, Kassian attempted to make a comeback with a professional tryout with the Anaheim Ducks, but it didn't work out. A number of weeks following his release, he opted to hang up his skates. Retirement wouldn't quite stick, though, as three months later he inked a deal with HC Sparta Praha of the Czech Extraliga.