Gabriel attended John Horn High School in Mesquite, Texas, where he played football, basketball, and ran track for the Jaguars athletic teams.

He earned Class 5A TSWA All-State as senior in 2008 after totalling 90 catches for 1,354 yards with 13 touchdowns for a 4–7 team with the school’s first playoff bid.

[3] Gabriel enrolled to play college football at Abilene Christian University, where he holds the record for most career touchdowns, from 2010 to 2013.

[12] In Week 9, against the Tampa Bay Buccaneers, he caught 34-yard pass from quarterback Brian Hoyer for his first career touchdown reception.

[19] He played a significant role for the Falcons throughout the season, which was successful and resulted in an appearance in Super Bowl LI, where they lost to the New England Patriots in overtime by a score of 34–28.

[26] On September 9, Gabriel made his Bears debut, catching five passes for 25 yards in the season-opening 24–23 road loss to the Green Bay Packers.

[30] During Week 3 against the Washington Redskins, Gabriel caught six passes for 75 yards and three touchdowns in the 31–15 road victory,[31] though he exited the game with a concussion.

[32][33] Gabriel was also the fourth player in Bears history to accomplish the feat in one quarter after Red Pollock (1935), Frank Minini (1948), and Gale Sayers (1965).