In addition to his work at KHIO, he has also held acting classes at Oslo Act, Det Multinorske, Musikkteaterhøgskolen, and has given workshops at Operahøgskolen, Teaterhøyskolen Copenhagen, Listaháskóli Íslands Reykjavik, Teatterikorkeakoulu Helsinki and at CITO Ouagadougou Burkina Faso.
Holter has also worked as an actor and director at a number of institutional theaters and private theatres, as well as produced performances in the open field.