He played college football for the Alabama Crimson Tide, where he was a part of the team that won the 2013 BCS National Championship Game.

Collins attended Dutchtown High School, in Geismar, Louisiana, where he was a two-sport star in football and track.

[21][22] Collins was reluctant to forgo his senior season at Alabama, but he was swayed by the NFL Draft Advisory Board's decision to grade him as a potential first-round pick.

[16] Collins acknowledged that passing up on the opportunities to compete for another national championship and continue his education at Alabama was difficult, but vowed that he would complete the necessary courses in order to ensure that he would graduate.

[28] The Giants originally owned the 40th pick, 8th overall in the second round, but made a trade with the Tennessee Titans in order to take Collins.

On October 19, 2015, Collins made his first career interception, picking off Sam Bradford and making five combined tackles in the Giant's 27–7 loss to the Philadelphia Eagles.

[35] On December 20, 2015, Collins recorded a season-high ten combined tackles and a pass deflection in a 38–35 loss to the Carolina Panthers.

With the selection of Darian Thompson in the 2016 NFL draft, Collins was able to switch back to his originally intended position of strong safety.

The following week, he made sixed combined tackles and recorded his first career sack on Drew Brees in a 16–13 victory over the New Orleans Saints.

[40] The following week the New York Giants played the Los Angeles Rams at Twickenham Stadium in London, and he made eight solo tackles and a season-high two interceptions off of Case Keenum, returning one for a 44-yard touchdown.

[41] On November 6, 2016, Collins recorded a season-high 12 combined tackles, a pass deflection, a sack, and intercepted Carson Wentz during the Giant's 28–23 win over the Philadelphia Eagles.

[42] He was named the NFC Defensive Player of the Week for the second consecutive game and was the first safety to accomplish that feat since Troy Polamalu.

The following week, he recorded five solo tackles and intercepted Andy Dalton in the fourth quarter of a 21–20 victory over the Cincinnati Bengals.

During a Week 11 matchup with the Chicago Bears, Collins made six solo tackles, three pass deflections, and intercepted Jay Cutler with 1:11 left on the clock to seal the 22–16 victory.

[43] Collins earned NFC Defensive Player of the Month for November, registering 30 combined tackles, a sack, and three interceptions.

[45] He finished his first season under new head coach Ben McAdoo with 125 combined tackles, four sacks, 13 pass deflections, five interceptions, and a touchdown in 16 starts.

Collins ended the season as the only player in NFL history to have over 100 solo tackles, more than two sacks, at least five interceptions, and with a minimum 12 pass deflections.

In the team's Week 13 win over the Chicago Bears, Collins suffered a partially torn rotator cuff and was placed on injured reserve four days later after it was announced he would have surgery to repair it.

[57][58] An unrestricted free agent for the 2019 season, Collins signed a six-year, $84 million contract with the Washington Redskins on March 13, 2019.

[61] In week 6 against the Miami Dolphins, Collins recorded a team high 12 tackles and sacked Josh Rosen once as the Redskins won their first game of the season 17–16.

[71] The following week against the Philadelphia Eagles, he recorded an interception off a ball that bounced off Dallas Goedert's foot, one pass deflection, and one fumble recovery.

[78] In Week 17 against the Indianapolis Colts, Collins intercepted a Nick Foles pass and returned it for a pick six touchdown in the 38–10 win.

When Hurricane Katrina hit the city in 2005, Collins and his family had to leave, and eventually settled in Geismar in Ascension Parish.

[82] As a child, Landon's idols were former running back Clinton Portis, retired quarterback Peyton Manning, and the late Sean Taylor, who was a safety for the Redskins when he was murdered - Collins wore No.

His father is currently a station director at the Coastal Bridge Construction Company in Baton Rouge, Louisiana, while his mother resides in Florida.

[15] The two have never directly addressed Landon's decision to choose Alabama over LSU, which causes the issue to remain a source of tension in their relationship.

[15] Following U.S. President Donald Trump's September 2017 comments where he said that any player that kneels during the National Anthem should be fired or suspended, Collins and Giants teammates Damon Harrison and Olivier Vernon all took a knee in their third game of the 2017 season against the Philadelphia Eagles.

[87] Collins also referenced his uncle who previously served in the Army as an additional source of conflicted feelings while taking a knee during the anthem.