[7] He later dropped Georgia and USC from his list and added Florida State,[8] but eventually announced his decision to attend LSU at the U.S. Army All-American Bowl.

[9] Peterson attended Louisiana State University, where he played for coach Les Miles's LSU Tigers football team from 2008 to 2010.

[16][17] By mid-season, Peterson tied for fourth in the league with seven passes defended, and was named the SEC's "Most Improved Player" by ESPN's Chris Low.

The Tigers were down by six points late in the fourth quarter when Peterson stepped in front of a pass from quarterback Greg McElroy to Julio Jones for what seemed like an interception.

With this added dimension to his game and his dominance as a cornerback, Peterson began being mentioned as a dark horse for the 2010 Heisman Trophy award, presented to the best college football player every year.

The Tiger defense suffocated Mississippi State's offense and Peterson strengthened his campaign with two acrobatic interceptions for LSU.

With the game tied 0–0 early in the first quarter, West Virginia went to attempt a mid-range field goal, and Peterson was able to leap from behind the line of scrimmage and block the kick.

Peterson struck the Heisman pose in the north end zone of Tiger Stadium, drawing a 15-yard unsportsmanlike conduct penalty.

[46] In his final collegiate game, the Cotton Bowl against Texas A&M, he had three kick returns for 81 net yards to go along with six total tackles.

On March 14, 2011, he participated at LSU's pro day and opted to stand on his combined numbers and only perform positional drills for scouts and team representatives.

[58][59] Head coach Ken Whisenhunt named Peterson the starting cornerback, alongside Greg Toler, to begin his rookie season.

He started the Cardinals' season-opener against the Panthers and scored his first career touchdown after returning a punt for an 89-yards in the fourth quarter to win the game 28–21.

[62] On November 6, 2011, during the overtime period, Peterson fielded a punt at the one-yard line, evaded several would-be tacklers, and returned it for the 99-yard touchdown in a 19–13 victory over the St. Louis Rams.

[68] He finished his rookie season with a sack, 64 combined tackles (59 solo), two interceptions, 13 passes defended, and two fumble recoveries in 16 games and 16 starts.

On September 16, 2012, Peterson had one carry for 17 yards, three combined tackles, a pass deflection, and intercepted Tom Brady in a 20–18 victory over the New England Patriots.

[73] On December 16, 2012, he recorded a season-high seven combined tackles and intercepted Detroit Lions quarterback Matt Stafford in a 38–10 victory.

[77] The Cardinals' new head coach Bruce Arians named Peterson the starting cornerback, opposite Jerraud Powers, to begin the 2013 season.

On September 29, he recorded two solo tackles and intercepted two passes from Tampa Bay Buccaneers quarterback Mike Glennon during a 13–10 victory.

[88] He began the season as the Cardinals' starting cornerback, opposite Antonio Cromartie, and no longer had to handle return duties due to the arrival of Ted Ginn Jr. On November 9, 2014, he made two solo tackles and intercepted two passes from Rams quarterback Austin Davis during a 31–14 victory.

[90] On December 7, Peterson recorded a season-high eight combined tackles and sacked Kansas City Chiefs quarterback Alex Smith in a 17–14 victory.

[94][95] On January 3, 2015, Peterson played in his first career postseason game and recorded two combined tackles during a 16–27 loss to the Panthers in the NFC Wild Card Round.

[98] Peterson was named the starting cornerback and had full-time punt return duties after the departure of Ted Ginn Jr.[99] On September 20, 2015, he recorded three solo tackles and intercepted Jay Cutler during a 48–23 win over the Chicago Bears.

[102] Although he started all 16 games, Peterson finished with a career low 35 combined tackles (35 solo), eight pass deflections, and made two interceptions.

[104] After defeating the Green Bay Packers 26–20 in the Divisional Round, in which Peterson had a 100-yard pick-six off Aaron Rodgers negated due to a defensive holding penalty, the Cardinals went on to the face the Panthers in the NFC Championship.

[110] In Week 3, Peterson recorded four combined tackles and intercepted Tyrod Taylor, catching the ball with one hand during an 18–33 loss to the Buffalo Bills.

[113] On December 20, 2016, for the sixth consecutive year, Peterson was selected to be in the 2017 Pro Bowl, along with teammates Larry Fitzgerald and David Johnson.

[115] Peterson remained as the Cardinals' de facto starting cornerback with Justin Bethel after Marcus Cooper departed in free agency.

[118] Overall, he finished the 2017 season with 13 punt returns for 88 net yards, 34 total tackles, one fumble recovery, eight passes defensed, and one interception.

[121] In Week 2 against the Los Angeles Rams, Peterson made eight tackles and intercepted Jared Goff as the Cardinals lost 34–0.

[149] In Week 16 against the Bengals, with all three members of the Steelers' three-safety package either injured or suspended, Peterson made his first career start as a safety.