During his college career, Walker was a standout player for the Florida State Seminoles, earning numerous accolades and awards. He was a two-time first-team All-ACC selection, a first-team All-American in 2016, and the ACC Defensive Player of the Year in 2016.
In the 2017 NFL Draft, the Denver Broncos selected Walker in the second round with the 51st overall pick. He spent the first three seasons of his NFL career with the Broncos, primarily serving as a backup defensive lineman and special teams player. In 2020, he signed a one-year contract with the Arizona Cardinals, where he appeared in 11 games and recorded 20 tackles, 2 sacks, and 2 forced fumbles.
In 2021, Walker returned to the Denver Broncos on a one-year contract. He played in 16 games, starting three of them, and recorded 26 tackles, 4 sacks, and one forced fumble. At the end of the season, he became an unrestricted free agent.
Overall, DeMarcus Walker is a talented and versatile player who has shown his ability to make an impact on the field as both a pass rusher and a run defender. With his skillset and experience, he is expected to draw interest from several NFL teams during the free agency period.