Gardiner was a member of the WCHL champion Tigers in 1924 and in 1927 won the Hart Trophy as the NHL's most valuable player after playing every minute of every game for the Canadiens.

[9] He was named the winner of the Hart Trophy as the league's most valuable player, nine votes ahead of Bill Cook of the New York Rangers.

[9] Gardiner again appeared in all 44 games the Canadiens played in 1927–28, but was loaned to the Chicago Black Hawks to start the 1928–29 season.

[5] Serving as a player-coach in Chicago, Gardiner appeared in 13 games as a player,[3] but posted a dismal 5–23–4 record as coach.

[3] His rights were sold to the Boston Bruins following the season, before he was purchased by the Philadelphia Arrows of the Canadian–American Hockey League who named him as their head coach.

Gardiner remained with the team, renamed the Philadelphia Ramblers in 1935-36, who subsequently joined the American Hockey League as an affiliate of the New York Rangers.

Conference tournament champion † Gardiner coached the Penn team for 1 games before turning control over to William Farson.