Gardner, who had also been drafted by the Toronto Toros of the World Hockey Association, instead turned pro with the Rockies' farm team the Rhode Island Reds.

The bulk of his rookie pro season was spent in the National Hockey League, however, where he scored an impressive 30 goals and 59 points in sixty games.

Gardner started well after the trade scoring nine points including seven goals in eleven games with the Leafs to finish the season.

After failing to make the roster to start the 1980-81 season, the Maple Leafs dealt Gardner, along with Dave Burrows to the Pittsburgh Penguins in exchange for Paul Marshall and Kim Davis.

His solid play in the American League earned him another chance to find his game at the NHL level when the Washington Capitals offered him a contract for the 1984-85 season.

Eleven years after retiring, while serving as the assistant coach for the Washington Capitals AHL affiliate the Portland Pirates, Gardner was pressed into action when the team was short on players due to injury.

This assist extended an impressive accomplishment for Gardner: During his pro career he suited up with seven different American Hockey League teams and he produced at a point-a-game or better for every one of them.

He guided the Scottish club to the EIHL Gardiner Conference Championship and a playoff-quarterfinal appearance, but did not have his contract renewed at the end of the 2012-13 season.

[10] In Mai 2013, Gardner was named head coach of Dutch Eredivisie side Tilburg Trappers, signing a two-year deal with the team.

[13] On June 29, 2016, Gardner took over the coaching job at fellow DEL2 side Löwen Frankfurt, working alongside sporting director Rich Chernomaz.