He played college football at Washington, and signed with the Oakland Raiders as an undrafted free agent in 2016.

Mickens played college football at Washington, where he appeared in the majority of his career by changing his jersey number from 4 to 1 during his junior and senior years before he qualified for the 2016 NFL draft.

[1] He had good, but unspectacular numbers, leading the team in receptions and receiving yards his junior and senior seasons but never cracking the Top 10 in the conference; he was the Huskies kick returner his freshman year, but only returned four punts over his college career, recording no touchdowns in either role.

[13] As a receiver, he recorded one reception prior to Week 15, but had four for 61 yards and two second-quarter touchdowns in a playoff-clinching 45–7 win over the Houston Texans.

[25] Mickens was the Buccaneers' kickoff returner for Super Bowl LV, a 31–9 victory over the Kansas City Chiefs.

[32] In the 2021 season, Mickens mainly contributed on special teams for the Buccaneers and Jaguars in 11 total games.

[37] On January 30, 2025, Mickens signed with the DC Defenders of the United Football League (UFL).