His leadership and on-field performance was one of the reasons for the continued success of Boise State football during his tenure.

[7] Near the end of the 2005 CFL season, Dinwiddie was signed to the practice roster of the Montreal Alouettes,[9] and was resigned by the team on December 8, 2005.

[10] This reunited him with Doug Berry, Winnipeg's head coach who been Montreal's offensive coordinator the year before.

[7] Dinwiddie's first significant playing time came early in the 2006 regular season finale in B.C., when Winnipeg's starting quarterback, Kevin Glenn, went down to an ankle sprain.

[10] During the off-season, before the 2007 CFL season, Dinwiddie attempted to join Arizona Rattlers of the Arena Football League, lasting for three weeks with the Rattlers before learning that his CFL contract precluded him from playing during the 2007 Arena Football League season.

[7][11] In the 2007 regular season, Dinwiddie's most noteworthy playing time came when Glenn went down to a knee injury against the Hamilton Tiger-Cats on September 15.

Berry decided to start Dinwiddie instead of Glenn in game 5 against the Calgary Stampeders because he "tried to shake up his troops to get in the win column.

During his 3 years as a backup in Winnipeg, his career CFL statistics are 58.2% completion percentage, for 1,581 yards, 6 Touchdowns and 9 Interceptions, for a Passer Rating of 73.8.

[17] On August 1, 2013, Hawkins was fired by the team after starting the season 2–3, and general manager Jim Popp replaced him as head coach.

[25] In 2019, Mitchell suffered a pectoral injury in Week 3 and was subsequently placed on the six-game injured reserve list.

The following week, Arbuckle got his first CFL start, in Saskatchewan, and threw for 262 yards en route to a 37-10 Calgary win.

On December 12, 2019, Dinwiddie was named the head coach of the Toronto Argonauts, the 45th in team history.

[28] The Argonauts also set a CFL record as the earliest to clinch a first place finish with six games remaining in an 18-game schedule.

[29] However, much like the only other team to finish with 16 regular season wins (the 1989 Edmonton Eskimos), the Argonauts were upset in the East Final.

In the East Division Final against Montreal, Kelly suffered a broken tibia, and Nick Arbuckle finished the game.