From 1946 to 1968 he was a trombonist in Kringkastingsorkesteret, playing solo in works arranged for his instrument.
[3] From 1968 to 1974, he was an associate professor of Norwegian folk music at the University of Bergen.
In the first phase, he mainly worked with Arne Bjørndal's folk music collection, before being granted a research fellowship to study the composer Christian Sinding.
From 1974 to 1988, Rugstad headed the music department of the Norwegian Broadcasting Corporation.
[4] Dagbladet had suggested Rugstad as a director of the Norwegian National Opera.