He has also been a member of the Carolina Panthers, Las Vegas Raiders, Houston Texans, Arizona Cardinals, and Green Bay Packers.

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.

[14] Throughout training camp, Douglas competed against Patrick Robinson, Jalen Mills, Ron Brooks, Ronald Darby, Jaylen Watkins, Aaron Grymes, and Sidney Jones for a role as a starting cornerback under defensive coordinator Jim Schwartz.

[15] Head coach Doug Pederson named him the fourth cornerback on the Eagles' depth chart to start the regular season, behind Darby, Mills, and Robinson.

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 27–20 loss.

[16] On September 17, 2017, Douglas earned his first career start at nickelback alongside Jalen Mills and Patrick Robinson and recorded four combined tackles (three solo), defended a pass, and had his first career interception on a pass thrown by New York Giants' quarterback Eli Manning to wide receiver Brandon Marshall during a 27–24 victory against the New York Giants.

On January 13, 2018, Douglas appeared in his first career playoff game, but was limited to special teams during a 15–10 victory against the Atlanta Falcons in the Divisional Round.

[20] During training camp, Douglas competed to be the starting nickelback and primary backup cornerback against Sidney Jones, Daryl Worley, Avonte Maddox, De'Vante Bausby, and Chandon Sullivan.

Head coach Doug Pederson named Douglas as the fourth cornerback on the depth chart to begin the regular season, behind starters Ronald Darby and Jalen Mills, as well as nickelback Avonte Maddox.

[24] Throughout training camp, Douglas competed against Ronald Darby, Jalen Mills, Avonte Maddox, Sidney Jones, and Cre'Von LeBlanc to be a starting cornerback.

[29] Head coach Matt Rhule named him the third cornerback on the depth chart, behind starters Donte Jackson and rookie Troy Pride, to begin the season.

[33] During training camp, Douglas competed to be a starting cornerback against Trayvon Mullen, Damon Arnette, Amik Robertson, Isaiah Johnson, and Nate Hobbs.

[36] On October 6, 2021, the Green Bay Packers signed Douglas off the Arizona Cardinals' practice squad, following injuries to starting cornerbacks Jaire Alexander and Kevin King.

On October 28, 2021, Douglas made a season-high nine solo tackles, deflected two pases, and had his first interception with the Packers on a haul mary pass thrown by Kyler Murray to wide receiver A. J.

[38] Leading into a Week 10 matchup against the Seattle Seahawks, defensive coordinator Joe Barry named Douglas a starting cornerback alongside Eric Stokes, supplanting Kevin King who had returned from injury.

[43] Head coach Matt LaFleur named Douglas the third cornerback on the depth chart to begin the regular season, behind starters Jaire Alexander and Eric Stokes.

He started in the Green Bay Packers' season-opener at the Chicago Bears and collected a season-high eight combined tackles (six solo) and had one pass deflection during their 38-20 victory.

[45][46] Before Week 10, head coach Sean McDermott named Douglas a starting cornerback alongside Dane Jackson, supplanting Christian Benford.

On January 21, 2024, Douglas made two combined tackles (one solo) and forced a fumble as the Bills lost 24–27 to the Kansas City Chiefs in the Divisional Round.

In Week 14, he made six combined tackles (four solo) before exiting in the third quarter of 42–44 loss at the Los Angeles Rams after suffering an injury while giving up a touchdown to Cooper Kupp.

On January 19, 2025, Douglas made six combined tackles (five solo) and secured a 27–25 Divisional Playoff win by recovering an onside kick in the final minute at the Baltimore Ravens.