Cosby, originally from Louisville, Kentucky, began playing football as a defensive back and wide receiver at the local DuPont Manual High School,[1] where he was captain and stood out as one of the best players in the category.

[2] Already from the first year and throughout his experience with the Cardinals Cosby played as a starter, covering the role of safety, only entering as a reserve in the first game of 2018 due to an injury suffered during the pre-season training period.

[3] Overall in five years with the Cardinals, he played 56 games, of which 55 as a starter, collecting 380 tackles, of which 280 solo, 10 interceptions, 5.0 sacks and three forced fumbles.

[4] Career personal bests are in bold[5] Cosby was not selected in the 2022 NFL draft and on May 12, 2022, signed a one-year, $207,000 contract with the Las Vegas Raiders as an undrafted free agent.

[7][8] On August 30, 2022, Cosby did not return to the active roster and was released by the Raiders, only to sign with the practice squad the following day.