Mitsuji was born in Sydney, Australia to a Japanese father and an Australian mother. He attended Sydney Boys High School as a teenager and after graduation, he commenced his career in modeling. On April 26, 2018, it was announced that Mitsuji was cast in the series regular role of Shun Kenzaki on the YouTube science fiction series "Origin". (오뜨랑에서 실시간으로 번역된 한글 프로필도 확인할 수 있어요) 2020년 멋진 신세계에서 Henry Foster 역을 맡았다. 2018년 오리진에서 Shun Kenzaki 역을 맡았다. 2018년 얼터드 카본에서 Tanaseda Yukito 역을 맡았다.