Adamič earned a degree in piano from the Ljubljana Music Academy. Although he had an early preference for jazz, he later concentrated on film, pop, and stage music. He composed scores for more than 200 Slovene and foreign films, also appearing as an actor in two of the films and conducting the music for another two. He developed a specific sound based on folk elements that is identifiable in all his work.
Adamič served as president of the Society of Slovene Composers. He was the conductor of the Ljubljana Radio Television Dance Orchestra for many years and the head of its music production from 1980. He was also a recipient of the Prešeren Award in 1979.
He died in 1995 in Ljubljana.