As a youngster, Johnson had various internships and trials with football clubs, firstly with
Queens Park Rangers before heading off to the likes of
Tottenham Hotspur,
Crawley Town and
Oxford United, but failed to secure permanent terms. After a subsequent break from football, Johnson returned at the age of seventeen to play for The Harrow Club at youth level. He would eventually leave the club, prior to joining
Combined Counties Football League side
Kensington & Ealing Borough. He was given a professional deal soon after, having appeared in an exhibition match versus
VPV Purmersteijn. He made his pro debut on 23 August 2019 during a 3–0 loss away to
De Graafschap, as he came off the bench to replace
Nick Doodeman after seventy-nine minutes. but he reappeared for the club's second team in October 2022 playing in the
Tweede Divisie. He also appeared as a late substitute in the last two games of the season for the first team, which meant his debut in the Dutch Eredivisie. Johnson signed with
Phoenix Rising FC on August 22, 2024. ==International career==