Gaup was born in
Alta,
Norway. He made his film debut in 1987, playing the leading role as Aigin in the film
Pathfinder. The film was nominated for
Best Foreign Language Film at the
1988 Oscars. He also appeared in a number of other films, including the 1991 film
The Miracle, the 1996 film
Breaking the Waves, and the 2008 film
The Kautokeino Rebellion as "
Aslak Hætta". As stage actor he has worked for various theatres, including
Beaivváš Sámi Teahter,
Den Nationale Scene and
Riksteatret. He has also performed and recorded
joik, a form of traditional Sami folk music. He participated in
Melodi Grand Prix 2021 alongside Marianne Pentha with the song "Pages". He had a minor role in
Let the River Flow, a 2023 Sámi historical drama inspired by the
Alta controversy. ==Personal life==