Mark Thompson

National Football League Prior to the 2018 NFL draft, Thompson worked out with the Atlanta Falcons. After going undrafted, he was signed by the Baltimore Ravens as an undrafted free agent on May 4, 2018. In preseason, he ran 31 times for 146 yards and caught 10 passes for 76 yards. He was released during final roster cuts before the start of the regular season. After having tryouts on September 4, September 5 and September 11, Thompson was re-signed by the Ravens to their practice squad on October 18, 2018. He was released from their practice squad on November 27, 2018. He became a free agent after the season. Thompson signed a reserve/future contract with the Detroit Lions at the conclusion of the 2018 season, on January 2, 2019. Later, on September 10, 2019, Thompson was signed to the practice squad of the Ravens. He was placed on the practice squad/injured list on September 18, before being released on September 23, 2019.

In January 2020, Thompson was signed by the Las Vegas Raiders to a reserve/future contract. He was waived on April 28, 2020. He had a tryout with the Carolina Panthers in September, but was not signed.

Houston Gamblers / Roughnecks 2022 After being out of football for a year, Thompson was chosen in the 28th round (227th overall) of the 2022 USFL draft by the Houston Gamblers. He served as the Gamblers' main running back, appearing in nine games and starting seven while posting a team-leading 114 rush attempts for 463 yards (a 4.1 average) with two rushing touchdowns. He also scored two receiving touchdowns, which made him third on the team in total points scored (24, behind Isaiah Zuber and Nick Vogel). His rushing touchdowns total set the spring football record for the 21st century. Thompson was named the USFL's offensive player of the week one time and finished with the second-highest total of rushing yards in the league, while also leading in rushing yards-per-game at 81.6.

On July 17, 2023, the New York Giants hosted Thompson for a workout.

Thompson became a free agent after the 2023 season and re-signed on December 24, 2023. Thompson and all other Houston Gamblers players and coaches were transferred to the Houston Roughnecks after it was announced that the Gamblers took on the identity of their XFL counterpart, the Roughnecks.

2024 Due to a knee sprain, Thompson missed the first three games of the season. In his first game back, against the Arlington Renegades, Thompson had nine carries for 34 yards and a touchdown, along with one reception for five yards in the 17–9 win. He ended up appearing in seven games, three as a starter for the 2024 Roughnecks, totaling 66 rushes for 226 yards (a 3.4 average) and five touchdowns.