Dunlop attended the Edinburgh University, studying violin with Camilo Ritter, vocals with Michael Poutiatine, and composition under Sir Donald Francis Tovey and Hans Gal. Isobel worked as a concert violinist and freelance composer after her graduation, also teaching at Downham and [url=https://discogs.com/artist/10515496]Westonbirt School[/url] in the 1930s. She served as an Assistant National Officer at the Edinburgh University between 1943 and 1948.

In 1949, Isobel Dunlop co-founded The Saltire Music Group with German opera conductor Hans Oppenheim (1892—1965), who lived in the UK since 1934. The ensemble was created under the auspices of the Saltire Society (a membership organization established in 1936 to study and disseminate Scottish cultural heritage and named after saltire, or "crux decussata," better known as Saint Andrew's Cross, on the Flag of Scotland). Dunlop also established The Saltire Singers, a prolific vocal quartet that branched from the main collective, and served as Saltire Music Group's Secretary until her retirement.