After starting the season 3–4, the Chiefs won their ninth game in week 14 over the Las Vegas Raiders clinching their ninth consecutive winning season, one short of the franchise record of 10. That 7-week stretch without a winning record was the Chiefs' longest stretch without a winning record since 2012 when they held a losing record the entire season. The Chiefs maintained a non-winning record until a week 9 victory over the Green Bay Packers. In Week 7, the Chiefs lost 3–27 to the Tennessee Titans, which is the fewest points scored in a game since Patrick Mahomes became the quarterback. The Chiefs' 20–38 week 5 loss to the Buffalo Bills, was the Chiefs' first double-digit loss in the regular season since 2017 and the Chiefs' first double-digit loss at home since 2014.
The Chiefs would lose their next two games to give them a 1–2 record after three games, which was their first losing record in 89 games, dating back to week 10 of the 2015 season. The win was the Chiefs' 15th consecutive win in September. The Chiefs opened the season on September 12 with a 33–29 victory over the Cleveland Browns. It was the franchise's largest victory over their rival. The Chiefs hosting the Raiders on December 12, a game in which they would win 48–9. In the offseason, the Chiefs announced they would once again retire their live horse mascot Warpaint to continue with their commitment to stop using Native American imagery. Tackle Eric Fisher was released and fullback Anthony Sherman retired. The Chiefs lost two of their longest tenured players in the offseason. On March 4, 2021, the Chiefs announced that they had officially renamed Arrowhead Stadium, GEHA Field at Arrowhead Stadium. 9.2.14 Week 15: at Los Angeles Chargers.
9.2.6 Week 6: at Washington Football Team.3.8 Signed and released in the offseason.