Lindsay, like his father Troy, played running back in high school. At South High School, Lindsay elected to wear the same jersey number as his father, 22. Playing for the Rebels, he chased the Denver Public School District record for rushing yards, which was set by his father in 1979. After a successful first three years of high school, Lindsay committed to playing for the University of Colorado Boulder. Shortly after surpassing his father's rushing record during his senior season, Lindsay suffered a severe ACL tear that brought an end to his high school career. Despite this injury, Mike MacIntyre, Colorado's coach, upheld the school's scholarship offer for the 2013 season. Apart from football, Lindsay also lettered in basketball as a freshman, and lettered all four years in track and field, where he ran sprints and relays and had personal bests of 10.9 seconds in the 100-meter dash, 22.2 in the 200 and 49.0 in the 400.
College career
Lindsay joined the Colorado team during the fall of 2013. He opted to redshirt during the 2013 season, during which time his work on the practice squad earned him the honor of "Offensive Scout Team Player of the Year."
2014 season
Before the 2014 season began, Coach MacIntyre began calling Lindsay the "Tasmanian Devil" due to his quickness and determination on the field. As a backup running back and kick returner back during the season, Lindsay played in all 12 of the school's games. He led the team in kick returns and return yards and finished fourth on the team overall in rushing yards. Lindsay averaged 4.9 yards per carry in his 79 carries of the season.
2015 season
Like the 2014 season, Lindsay saw action in all of the Buffaloes' games. He led the team in rushing attempts and rushing yards, averaging 4.7 yards per carry. Lindsay scored seven touchdowns during the season, 6 rushing and 1 receiving. Despite only being a sophomore, Lindsay was elected by his teammates and coaches to be a team captain.
2016 season
During the 2016 season, he rushed for 1,252 yards on 244 carries for an average of 5.1 yards per carry.
2017 season
During his senior season in 2017, he rushed for a career-high 281 yards against Arizona. During the 2017 regular season, he ranked ninth among all Division I FBS players with 1,474 rushing yards. Lindsay finished the 2017 season with the most rushing attempts in Division I play. He was selected as a semifinalist for the Doak Walker Award for the nation's top running back. Lindsay set the Colorado career record for all-purpose yards and yards from scrimmage and ranked second in school history in rushing yardage and fifth in points scored.
College statistics
Professional career
2018
Lindsay signed with the Denver Broncos as an undrafted free agent on May 1, 2018. He made the Broncos' final roster after an impressive preseason, and was named the No. 3 running back on the depth chart behind third-round rookie Royce Freeman and veteran Devontae Booker. In Week 1, against the Seattle Seahawks, he rushed for 71 yards on 15 carries and recorded two receptions for 31 yards and a receiving touchdown. The following week, in a 20–19 victory over the Oakland Raiders, Lindsay ran for 107 yards and had one reception for four yards. He became the first undrafted player in NFL history with 100+ scrimmage yards in each of their first two games. During Week 3 against the Baltimore Ravens, Lindsay was ejected for throwing punches after a fumble. He was held to 20 rushing yards as the Broncos lost 14–27. In Week 4, on Monday Night Football against the Kansas City Chiefs, Lindsay had a nice game with 69 rushing yards and added a rushing touchdown. In Week 11, in a 23–22 victory over the Los Angeles Chargers, Lindsay recorded his first multi-rushing touchdown game. In a Week 12 victory over the Pittsburgh Steelers, he had a season-high 110 rushing yards and a rushing touchdown. In a Week 13 game against the Cincinnati Bengals, he rushed for a career-high 157 yards and two touchdowns, earning him the AFC Offensive Player of the Week award. On December 18, 2018, Lindsay was voted to his first Pro Bowl making him the first undrafted offensive rookie in NFL history to be voted to a Pro Bowl. On December 24, 2018, Lindsay, who injured his wrist on Monday Night Football against the Oakland Raiders, was placed on injured reserve ahead of the Broncos’ final season game. He finished his first season with 1,278 total yards from scrimmage and 10 touchdowns while splitting carries almost evenly with Royce Freeman. He was named to PFWA's All-Rookie Team, becoming the fourth Denver Broncos running back to receive this award, joining Bobby Humphrey, Terrell Davis, and Olandis Gary.
2019
Lindsay made his return from injury in Week 1 against the Oakland Raiders on Monday Night Football. In the game, Lindsay rushed 11 times for 43 yards and caught four passes for 23 yards in the 24-16 loss. In Week 3 against the Green Bay Packers, Lindsay rushed 21 times for 81 yards and two touchdowns and caught four passes for 49 yards as the Broncos lost 27-16. In Week 5 against the Los Angeles Chargers, Lindsay rushed 15 times for 114 yards and one touchdown and caught four passes for 33 yards as the Broncos won their first game of the season by a score of 20-13. In Week 16 against the Detroit Lions, Lindsay rushed 19 times for 109 yards and a touchdown during the 27–17 win. In the season finale against the Oakland Raiders, Lindsay surpassed 1,000 yards rushing to become the first undrafted player in league history to do so in two consecutive seasons.
