He played as a quarterback with the Stampeders and the BC Lions, where he won the 2006 Grey Cup and was named the game's MVP.

Dickenson attended Charles M. Russell High School in Great Falls, Montana, was an excellent student, and lettered in football, basketball, and golf.

Dickenson also got significant playing time when Garcia got injured in the first quarter of the West Semi-Final against Saskatchewan.

In 1998, Dickenson made his second CFL start when Calgary played in Winnipeg on July 24 because Garcia was sidelined with a knee injury.

Despite suffering some injuries during the season, Dickenson was able to guide Calgary back to the Grey Cup game.

In October, he signed with the Miami Dolphins following an injury to Jay Fiedler, and served as their third QB until December 3.

He finished the season as the third QB for the Detroit Lions for their final two games after Joey Harrington was diagnosed with an irregular heartbeat.

Dickenson signed as a free agent with the BC Lions in 2003, reuniting him with his head coach in Calgary, Wally Buono.

In 2004, Dickenson began the season as the Lions' starting quarterback, but gave way to backup Casey Printers after suffering a knee injury.

Printers put on a dominating performance for the rest of the season, and won the CFL's Most Outstanding Player award.

In the West Division Final against the Saskatchewan Roughriders, Printers was forced to leave the game with a shoulder injury in the fourth quarter, with the score tied 14-14.

Dickenson, having recovered from knee surgery and shared quarterbacking duties with Printers late in the season, played the rest of the game and threw a touchdown pass in the Lions' 27–25 overtime victory.

[8] Dickenson would start and play the entire Grey Cup game against the Toronto Argonauts, which the Lions lost by a score of 27–19.

Dickenson emerged as the starter, and was instrumental in leading the Lions to an 11–0 start (where he played in 9 of the 11 games), en route to a league-best 12–6 season finish.

He fell just short of the attempts required to set a further mark with a 74.0% completion rate, due to 4 games missed because of a concussion.

He led the Lions to the franchise's 5th Grey Cup title on November 19, 2006, with a 25–14 win over the Montreal Alouettes.

Dickenson's 2007 season was interrupted early by a serious concussion received on a hit from Saskatchewan's Fred Perry.

Dickenson's only playing time that season came in the Labour Day Classic filling in for an injured Henry Burris.

Calgary won games with three different starting quarterbacks: Drew Tate, Kevin Glenn, and Bo Levi Mitchell.

Prior to the 2014 season, Calgary signed Dickenson to a three-year contract extension as offensive coordinator and added assistant head coach to his title.

On December 12, 2022, it was announced that Dickenson had been named the team's general manager in addition to retaining his head coaching duties.