He played college football for the Rutgers Scarlet Knights and was selected by the Tennessee Titans in the sixth round of the 2009 NFL draft.

[4] He ended his college career with 148 tackles, 2 interceptions, 20 pass breakups and finished second in the Big East in kickoff returns as a senior.

[12] Throughout training camp, he competed for the fifth cornerback spot on the roster against rookie Ryan Mouton, DeMarcus Faggins, Tanard Davis, and Jeremy Haynes.

[13][14] Head coach Jeff Fisher named McCourty the fourth cornerback on the Titans' depth chart to start the regular season, behind Cortland Finnegan, Nick Harper, and Cary Williams.

[17] On October 4, 2009, McCourty earned his first career start in place of Cortland Finnegan, who suffered a hamstring injury the previous week.

[18] The following week, he started his second consecutive game in the absence of Finnegan and recorded a season-high eight combined tackles during their 31–9 loss against the Indianapolis Colts.

[20] McCourty entered training camp competing for the job as the starting cornerback against Ryan Mouton, rookie Alterraun Verner, and Tye Hill after the role was left vacant by the departure of Nick Harper during the off-season.

[22] He started the Tennessee Titans' season-opener against the Oakland Raiders and recorded a season-high eight combined tackles and a pass deflection in their 38–13 victory.

[28] On January 28, 2011, the Tennessee Titans announced the firing of head coach Jeff Fisher after a 16-year tenure and a disappointing 6–10 season in 2010.

[30] Head coach Mike Munchak named McCourty the starting cornerback, opposite Cortland Finnegan, to begin the 2011 regular season.

[31] In Week 2, McCourty collected four solo tackles, broke up a pass, an interception, and made his first career sack on Baltimore Ravens' quarterback Joe Flacco during their 26–13 victory.

[34] He finished the season with a career-high 103 combined tackles (83 solo), 13 pass deflections, two interceptions, a sack, and a forced fumble in 15 games and 15 starts.

[36][37][38] McCourty and Verner entered the regular season as the starting cornerback duo after Cortland Finnegan departed to the St. Louis Rams in free agency.

[41] On December 17, 2012, he made five combined tackles, two pass deflections, and intercepted quarterback Mark Sanchez twice during a 14–10 victory against the New York Jets.

In Week 6, McCourty made a season-high nine combined tackles and forced a fumble as the Titans lost 20–13 at the Seattle Seahawks.

[48] In Week 6, McCourty recorded a season-high 11 combined tackles (ten solo) and a pass deflection in the Titans' 16–14 win against the Jacksonville Jaguars.

[58] On October 27, 2016, McCourty collected a season-high 11 combined tackles (eight solo) and two pass deflections in their 36–22 win against the Jacksonville Jaguars.

[64][12] Throughout training camp, he competed for a job as the starting cornerback against Joe Haden, Jamar Taylor, and Briean Boddy-Calhoun.

Head coach Hue Jackson named him the starting cornerback, alongside Jamar Taylor, after the Browns released Joe Haden.

[67] On October 15, 2017, McCourty made a solo tackle, deflected a pass, and returned an interception by Deshaun Watson for a 56-yard touchdown in a 33–17 loss at the Houston Texans.

[76] In the third quarter, with the Patriots leading 3–0, McCourty broke up a pass in the end zone to Rams receiver Brandin Cooks, preventing a touchdown.

Jason and Devin McCourty jointly delivered the 2019 commencement address at Rutgers; they also received honorary doctorates from their alma mater.