Douglas started his college career at Nassau Community College. After redshirting in 2012, he recorded 83 tackles and five interceptions over the 2013 and 2014 seasons. In 2015, he transferred to West Virginia University. During his first season at West Virginia, he appeared in 11 games and recorded seven tackles and an interception. As a senior in 2016, Douglas was named first-team All-Big 12 after he tied for the nation lead with eight interceptions. He also had 70 tackles and a sack.
Professional career
Coming out of West Virginia, Douglas was projected to be a third to fifth round pick from the majority of NFL draft experts and analysts. He received an invitation to the NFL combine and completed all of the required combine and positional drills. On March 31, 2017, Douglas participated at West Virginia's pro day and opted to run the 40, 20, and 10-yard dash once again while also performing positional drills. Team representatives and scouts from all 32 NFL teams attended to scout Douglas, K. J. Dillon, Shelton Gibson, Tyler Orlosky, and 14 other prospects. He was ranked the 19th best cornerback prospect in the draft by NFLDraftScout.com. The Philadelphia Eagles selected Douglas in the third round of the 2017 NFL Draft. He was the 17th cornerback selected in the draft and the second cornerback taken by the Eagles after they selected Sidney Jones in the second round. He competed with Patrick Robinson, Jalen Mills, Ron Brooks, Ronald Darby, Jaylen Watkins, Aaron Grymes, and Sidney Jones throughout training camp for the starting cornerback position. Head coach Doug Pederson named him the fourth cornerback on the Eagles' depth chart to start the regular season, behind Ronald Darby, Jalen Mills, and Patrick Robinson. Douglas was inactive for the Philadelphia Eagles' season-opening 30-17 victory over the Washington Redskins. During the second quarter, starting cornerback Ronald Darby dislocated his ankle, sidelining him for 4–6 weeks. On September 17, 2017, Douglas made his professional regular season debut against the Kansas City Chiefs and finished with four solo tackles and a pass deflection in the 20-27 loss. The following week, he earned his first career start in place of Ronald Darby and recorded four combined tackles, defended a pass, and made his first career interception after picking off a pass from New York Giants' quarterback Eli Manning during the 27-24 victory. Douglas finished his rookie season with 25 tackles, 2 interceptions, and 11 passes defended. The Eagles went on to win Super Bowl LII 41-33 against the New England Patriots. Pro Football Focus gave Douglas an overall grade of 61.2, which ranked 87th among all qualifying cornerbacks in 2017.
