Harris started for Miami Northwestern High School during his last two years; he was unbeaten (30-0) and led the team to two state championships.

In his senior year, Harris broke the state record for passing touchdowns and won the 2007 High School Football National Championship.

During his freshman year of college in 2008 with the Miami Hurricanes, he split time with Robert Marve in a two-quarterback system.

After the Emerald Bowl in late December, Marve transferred to Purdue, effectively making Harris the undisputed starter for the rest of his career as a Hurricane.

That year, he would lead Northwestern to an undefeated season and its third state championship while completing 275-of-425 passes for 3,542 yards, 35 touchdowns, and six interceptions.

As a senior in 2007, under his leadership, the team went on to another undefeated season and state title,[1] as well as the high school football national championship.

In a July 31, 2009, interview with Dan Le Batard, Harris told the world that he will pick up his Heisman Trophy wearing a pink suit and with a "pimp cup" in hand.

[6] During the first game of his sophomore season against #18 Florida State, Harris went 21-of-34 for 386 passing yards (a career-high and 10th highest in school history) with two touchdowns and also ran for a score in Miami's 38-34 upset road victory.

[7] In the second game of the 2009 season versus the Yellow Jackets at home, Harris completed 20-of-25 passes for 270 yards and three touchdowns—and the 20th-ranked Hurricanes snapped a four-game losing streak against #14 Georgia Tech with a 33-17 victory on September 17, 2009.

In the third game of the season against conference rival Virginia Tech, Harris struggled, throwing for nine completions out of 25 passing attempts, 150 yards, and no touchdowns in a 31-7 loss.

In a losing effort in overtime versus the Clemson Tigers, Harris put up 256 passing yards, two touchdowns, and three interceptions.

In overtime, after a 20-yard Graig Cooper run, Harris and the Hurricane offense failed to push in the possible game-winning touchdown.

The ninth game brought a change for the BCS 17th-ranked Hurricanes,[8] as a 24-17 halftime lead against the Virginia Cavaliers broke into a dominant second half.

In the final game at home for the Hurricanes against the Duke Blue Devils on November 21, Harris went 25-for-43, 348 yards passing, two touchdowns, and one interception.

As a sophomore, Harris led Miami to a 9-4 record and a #19 ranking from the AP poll while throwing for 3,352 yards, 24 touchdowns, and a pass efficiency rating of 140.09.

The Miami Hurricanes finished with a record of 7-6 as their head coach, Randy Shannon, was fired near the season's end on November 27, 2010.

[16] On August 25, 2011, Harris was ruled ineligible to play the first game of the 2011 season for his involvement with the Nevin Shapiro scandal.

[19] On October 15 as the Hurricanes jumped out to a 27-10 halftime lead and claimed a 30-24 victory in Chapel Hill, N.C against a 5-1 North Carolina Tarheel team.

[26] Following his time in the United States, Harris came north to Canada and joined the Edmonton Eskimos of the Canadian Football League (CFL) on February 6, 2013.