Tømmeraas was born in Solbergelva, a suburb in the city of Drammen. He grew up with his parents, Bjorn Olav and Runi Tømmeraas, in the town of Drammen. He has a younger brother, Teodor. He attended Killingrud Ungdomsskole, a private arts school. In 2017, Tømmeraas started serving Norway's compulsory military service for a year, finishing at the age of 20.