[1][2] He played college football for the Georgia Tech Yellow Jackets, earning third-team All-American honors in 2009.

[10] Thomas attended West Laurens High School in Dexter, Georgia, where he was a three-sport star in basketball, football, and track.

[11] He played wide receiver for the Raiders football team under the direction of then head coach John Kenny.

He earned a fourth-place finish in the triple jump event at the 2006 Georgia Olympics after clearing a personal-best mark of 13.92 meters (45–4).

[15] Under Yellow Jackets head coach Chan Gailey, Thomas sat out the 2006 season as a redshirt freshman.

[19] Thomas made his collegiate debut in the 33–3 victory over Notre Dame, recording a single reception for nine yards.

[20] He scored his first collegiate touchdown on a 56-yard pass from Taylor Bennett in the Yellow Jackets' fourth game against Virginia.

[15][27][28] Despite playing in a heavily run-oriented system, as one of the team's few experienced players, Thomas recorded relatively high numbers for the Yellow Jackets.

[30] In the 27–0 victory over Duke on October 4, he caught nine receptions for 230 yards, the second-most in a single game in school history.

[15][31] Thomas started his senior season strong with four receptions for 101 receiving yards in a 37–17 victory over Jacksonville State.

[35] Georgia Tech finished the regular season with a 10–2 record and qualified for the ACC Championship Game against Clemson.

[38][39] Overall in 2009, during his redshirt junior year at Georgia Tech, Thomas had a breakout season with 46 receptions for 1,154 yards and eight touchdowns.

[50] Thomas had the second-most catches by a rookie in franchise history, trailing only Eddie Royal, who had nine in a game against the Oakland Raiders in 2008.

[51] The highlight of Thomas's season came when he beat All-Pro cornerback Darrelle Revis for a 17-yard touchdown when the Broncos hosted the New York Jets in a 24–20 loss in Week 6 on October 17.

[55] On February 10, 2011, it was announced that Thomas had torn his achilles tendon while working out and was expected to miss a majority, if not the entirety, of the 2011 season.

On January 8, 2012, in the Wild Card Round, Thomas caught the game-winning, 80-yard touchdown pass from Tebow on the opening play of overtime to beat the Pittsburgh Steelers by a score of 29–23.

[70] Thomas was coming off surgery to remove pins in his left pinkie when quarterback Peyton Manning signed with the Broncos during the 2012 offseason.

[71][72] Manning noted during training camp that Thomas's "size, strength and speed just allow you to do certain things with him that other players just can't do.

[77] Thomas set regular-season career highs in both catches, with nine, and receiving yards, with 180, in the road loss to the New England Patriots on October 7, 2012.

[80][81] Thomas registered three catches for 37 yards and one touchdown in the Broncos' 2OT Divisional Round loss to the Baltimore Ravens in the playoffs.

[88] Thomas's 161 receiving yards were the second-most in franchise history for a season-opening game, trailing only Shannon Sharpe's 180 in the Broncos' 1995 regular season opener.

[112] On October 19, 2014, against the San Francisco 49ers, Thomas caught Peyton Manning's all-time record-breaking 509th touchdown pass.

Reports indicated that the tag was non-exclusive, which meant that Thomas could negotiate with other teams, and the Broncos held the right to match any offer, or receive two first-round picks as compensation.

[123] On July 15, 2015, Thomas signed a five-year, $70 million contract extension with the Broncos, just hours before the deadline for franchise players.

[130] Following a Week 9 loss to the Kansas City Chiefs, where Peyton Manning was benched for a stint in favor of Brock Osweiler, Thomas's production slightly dropped.

[140] Going into the 2016 season, the Denver Broncos lost both quarterbacks that contributed to the team's Super Bowl run; Manning to retirement,[141] and Brock Osweiler to the Houston Texans.

[151] From Weeks 8 to 10, he recorded three consecutive games with a receiving touchdown respectively against the Philadelphia Eagles, New England Patriots, and Cincinnati Bengals.

[162] During Week 16, Thomas was carted off the field in the second half of a 32–30 loss to the Philadelphia Eagles with an apparent Achilles injury.

[168] Three days later, on September 2, 2019, the Patriots re-signed Thomas to a one-year contract, but he never played a regular-season game for the team.

[196][197] After Thomas's death, his brain was donated to Boston University for examination, which tested positive for chronic traumatic encephalopathy (CTE), a neurodegenerative condition associated with repeated head trauma.