Kahmari Montgomery is an American track and field sprinter specializing in the 400 m for Nike. He was the men's 400 m champion at the USA Championships in 2018, and at the NCAA Division I Championships in 2019. He represented the United States in the 4 × 400 m relay at the World U20 Championships in 2016 and at the inaugural Athletics World Cup in 2018, earning gold medals in both competitions.

The 400 metres, or 400-meter dash, is a sprint event in track and field competitions. It has been featured in the athletics programme at the Summer Olympics since 1896 for men and since 1964 for women. On a standard outdoor running track, it is one lap around the track. Runners start in staggered positions and race in separate lanes for the entire course. In many countries, athletes previously competed in the 440-yard dash (402.336 m)—which is a quarter of a mile and was referred to as the "quarter-mile"—instead of the 400 m (437.445 yards), though this distance is now obsolete.