Mickens entered the National Football League (NFL) after receiving All-American honors at Texas A&M University.
Mickens grew up in El Paso, Texas, where he attended Andress High School and was a Division 1-5A All-State running back in the 1990, 1991 football seasons.
While in high school, he played against the Midland Lee Rebels football team to capture the Regional Championship.
He was one of the top coverage cornerbacks in the country and was an All-American and All-Southwest Conference player in both his junior and senior years.
He played in 126 games with 36 starts over the course of his first eight seasons while registering 365 tackles, 79 passes defended, 11 INT, four forced fumbles and six sacks.
He signed a one-year contract with the Browns as a free agent prior to the 2005 season and played in all 16 games, starting three, and recording 33 tackles and 16 passes defended.