He played college football for the Ohio State Buckeyes and was selected by the New Orleans Saints in the first round of the 2017 NFL draft.

Lattimore was named the 2017 Defensive Rookie of the Year and made four Pro Bowls with the Saints before being traded to the Commanders midway through the 2024 season.

[8] Coming out of Ohio State, Lattimore was projected to be a first round pick by the majority of National Football League (NFL) experts and analysts.

[16][17] The Saints were expected to bring Lattimore along slowly and allow him to sit behind starters Delvin Breaux and P. J. Williams and compete for the role as the third cornerback on the depth chart against Ken Crawley and De'Vante Harris.

[18] Head coach Sean Payton named him the third cornerback behind P. J. Williams and Ken Crawley after Breaux suffered a fractured fibula on August 16.

Lattimore made his NFL debut on Monday Night Football in the season-opener against the Minnesota Vikings and recorded four solo tackles in the 29–19 loss.

[20] Lattimore left the game in the fourth quarter and was placed in concussion protocol after colliding with teammate Vonn Bell as they both tackled wide receiver Brandin Cooks.

[28] Lattimore was named the NFL Defensive Rookie of the Year after recording 52 tackles, 18 pass deflections, five interceptions, and a touchdown in 13 games.

[30] On January 7, 2018, Lattimore started his first NFL playoff game and recorded two solo tackles and a pass deflection during a 31–26 NFC Wild Card round victory over the Carolina Panthers.

[31] The following week, he made four solo tackles and deflected a pass in a 29–24 road loss to the Vikings in the NFC Divisional round, which became known as the Minneapolis Miracle.

[32] In the season-opener against the Tampa Bay Buccaneers, Lattimore primarily covered wide receiver Mike Evans, who caught seven passes for 147 yards including a 50-yard touchdown.

[35] Two weeks later against the Buccaneers, Lattimore intercepted Jameis Winston in the endzone and forced a fumble off Chris Godwin in a 28–14 road victory.

[38] In the NFC Championship game against the Los Angeles Rams, Lattimore made six tackles in the controversial 26–23 overtime loss.

[46] In Week 8 against the Chicago Bears, Lattimore recorded his first interception of the season off a pass thrown by Nick Foles during the 26–23 overtime win.

[66] He denied that the gun was stolen and was sentenced to a year of probation and fined $1,000 after pleading guilty to a misdemeanor charge of failing to inform officers that he was in possession of a concealed handgun, which he held a permit to carry.