Gregory attended Arizona Western College from 2011 to 2012. As a freshman in 2011, he had 82 tackles and nine sacks. He missed the 2012 season due to a broken leg. He committed to Purdue University, but was academically ineligible and decided to attend the University of Nebraska–Lincoln. In his first year at Nebraska, he started 10-of-13 games, recording 64 tackles, 10.5 sacks and one interception that he returned for a touchdown. His 10.5 sacks led the Big Ten. He was named a first-team All-Big Ten and was Nebraska's Defensive MVP. Sporting News listed Gregory as their preseason number 5 player in college football for 2014. For the season he had 50 tackles and seven sacks. He decided to forgo his senior season and enter the 2015 NFL Draft.
Collegiate statistics
Professional career
As early as May 2014, Gregory was projected as a high first-round selection in the 2015 NFL Draft by various mock drafts. However, after failing the 2015 NFL Scouting Combinedrug test for marijuana, he was looked over during the first round of the draft and fell heavily to the second round, until being selected by the Dallas Cowboys. In 2015, although he showed promise during preseason and in the season opener against New York Giants, he suffered a high ankle sprain in the fourth quarter that forced him to miss the next four games and held back his development. He made his return to the field in week 7 against the Giants, however, it wasn't until the team's week 10 loss to the Tampa Bay Buccaneers that Gregory posted his first professional tackle, making one solo and one assisted tackle in the game. He didn't have a sack during the season, but still managed 16 quarterback pressures and one tackle-for-loss. On February 19, 2016, Gregory was suspended for the first four games of the season due to violating the league's substance abuse policy. A few months later, Gregory failed a second drug test, checked into an undisclosed treatment facility and was removed from the team's roster. He received an additional 10-game suspension, making him ineligible to return to the Cowboys until December 19. On November 11, it was reported that Gregory supposedly failed another drug test and was facing a yearlong suspension added on to his current 14-game suspension. Gregory was activated from his consecutive suspensions on December 26, prior to a Week 16 matchup against the Detroit Lions. His year-long suspension was not in place at the time so he could make his 2016 season debut. In the game, he was able to play through an oblique strain he suffered in the second quarter, while posting two tackles and one quarterback hurry. With the team suffering multiple injuries along the defensive line, he started in the last game of the season against the Philadelphia Eagles, recording his first career sack, one tackle for loss, a quarterback hurry and was second on the team with seven tackles. Although there was a possibility that the NFL would delay the appeal hearing for his latest suspension and allow him to play in the postseason, the meeting was held on January 3, 2017, with the league officially announcing that Gregory would be suspended for the playoffs and at least for one season on January 5, after allegedly missing a scheduled drug test. On July 17, 2018, Gregory was reinstated by the NFL on a conditional basis, allowing him to report to training camp and participate in meetings, but is not permitted to participate in games or practices until the conditions are met. He was fully reinstated by the league the following week. On August 30, he visited with the NFL's chief medical director in what was reported to be a proactive meeting to discuss his treatment and progress. In early September, a report surfaced in the media that Gregory may have suffered a substance abuse relapse during the month of August. Although he was called to the New York League Headquarters for a private meeting, no further discipline was applied. In 2018, he surprised observers by becoming a reliable defender on one of the best defenses in the league, after missing most of the previous two seasons because of suspensions. He was a backup right defensive end behind Tyrone Crawford, that played mostly on passing downs. He started in the season finale against the New York Giants, when Crawford sat out to rest for the playoffs. He played in 14 games, recording 25 combined tackles, six sacks, and two forced fumbles. The Cowboys had a 6-0 win record in games where Gregory registered a sack. On February 26, 2019, Gregory was suspended indefinitely by the NFL for violating the league's substance abuse policy and the terms of his conditional reinstatement. On April 2, 2019, the Cowboys extended Gregory's contract through the 2020 season. In March 2020, ESPN reported that Gregory filed for reinstatement with the NFL.
Personal life
Gregory has a daughter, Sophia, born in fall 2016.
