Ohlson studied violin and music theory in Uppsala and Stockholm. He studied voice in Stockholm with Joseph Hislop, Augustin
Kock and John Forsell.
He made his debut at the Stockholm Royal Opera in 1941 as Ottavio. He sang at the
Stockholm Royal Opera 1941–66, and at the Drottningholm Festival 1946–1968.
His repertory included: Albrecht (Mathis der Maler, Swedish premiere in 1950), Lamberto (Il maestro di musica by Pergolesi),
Beppe, Belmonte, Tamino, Lykov,
Pastor Adams (Peter Grimes),
? (Birgitta by Berg), ? (Aniara), ? (Die Kluge), Snout (A midsummer night's dream), Hoffmann, Fenton, Rinuccio, Andrej
Pâris, ? (Tranfjädrarna), Andres (Wozzeck, Swedish premiere in 1957), ...
1966–74, he taught singing at the conservatory in Aalborg, and from 1974 in Stockholm and Uppsala.
Reference:Richard T. Soper Nordic voices, Manchester Center (Vermont), 2010
Reference: Kutsch & Riemens