Radjen began playing college soccer at Cleveland State University in 2012, where he played for two seasons and making 36 appearances for the Vikings and was named Horizon League All-Newcomer Team in his freshman season.
[3] Whilst at college, Radjen spent a season in the USL PDL with West Virginia Chaos.
In April 2017, Radjen was announced as being on the roster for side New York Cosmos who played in the[6] via their first team who competed in the NASL.
[11] After a season with Teleoptik, Radjen signed a one-year deal with Serbian SuperLiga club OFK Bačka on July 31, 2020.
[12] He made his debut for the club on September 13, 2020, appearing as an injury-time substitute during a 2–1 loss to Mladost Lučani.