He played for the BC Lions for six seasons before joining the Winnipeg Blue Bombers in 2016 as a free agent, where he was named the 2017 Most Outstanding Canadian after leading the league in rushing and setting the record for single-season receptions by a running back.

After high school in Winnipeg, Harris joined the Vancouver Island Raiders of the Canadian Junior Football League.

During his junior career, he led the Raiders to three national championships (2006, 2008, and 2009) and broke a number of British Columbia conference and CJFL records, including all-time touchdowns and scoring.

[4][5] The head coach and general manager of the BC Lions, Wally Buono, took notice of Harris' talents in junior football and claimed him as a territorial exemption on May 22, 2008.

Harris saw his role expand and he took over as the starting running back in mid-season, finishing with 853 total yards and eight touchdowns.

[9][10] In the playoffs, Harris was named the Canadian player of the week for his performance in the Lions' win over the Edmonton Eskimos in the West Division Final.

A week later, Harris was named the Most Outstanding Canadian at the Grey Cup, scoring a touchdown and rushing for 65 yards over 10 carries in the Lions 34–23 win over the Winnipeg Blue Bombers.

[17] He missed the final six regular season games as well as the team's crossover East Semi-Final loss in Montreal.

Immediately following playoff elimination as a pending free-agent, Harris expressed his displeasure with the BC Lions organization, putting his future with the club in doubt.

In the West Semi-Final in Saskatchewan, Harris rushed for 153 yards and a fourth quarter touchdown en route to the Blue Bombers' 23-18 victory, the team's first playoff win since the 2011 East Final.

During the 2019 CFL season, Harris surpassed the 8,000 rushing yard mark for his career, in a game against the Argonauts at home.

[27] In Winnipeg's final regular season game, Harris broke the record previously held by Normie Kwong for career rushing yards by a Canadian player in the CFL; the play on which he broke the record set up Winnipeg's game winning field goal over Calgary.

[30] Meanwhile, Bob Irving, a local radio announcer and the lone voter for Harris defended him; “I believe that a 2-game suspension, 2 missed game cheques and public embarrassment in July was punishment enough—I proudly voted for him.”[31] Harris helped the underdog Blue Bombers win their first Grey Cup since 1990 against the Hamilton Tiger-Cats in the 107th Grey Cup game.

[34] Following the win of his hometown team Harris said "I'm so proud to be a Winnipegger and I can't wait to get back and share this with all them.

On October 22, 2021 the Bombers announced that they had placed Harris on the six-game injured list because of a knee injury he suffered when he scored a touchdown against the Edmonton Elks.

[38] On February 8, 2022, Harris agreed to terms with the Toronto Argonauts after spending six seasons with the Winnipeg Blue Bombers.

Harris returned to the active roster in the East Division Final vs. the Montreal Alouettes and scored his first touchdown with the Argonauts.

One week later, Harris helped Toronto win the 109th Grey Cup by defeating his former team, the Blue Bombers.

[51] Harris cites his idols as former Winnipeg Blue Bombers running back Charles Roberts, and hockey player Steve Yzerman.

[12] Throughout his professional career, Harris wore #33 as a tribute to a Vancouver Island Raiders teammate who died in a car crash in September 2008.