Clark was born at 125 Westmorland Road in Newcastle, and made his career in music. He was a true European; knew ten languages and was in touch with the major figures in European avant-garde music - Berg, Webern, Prokofiev, Ravel and Strauss, as well as being a personal friend of Stravinsky. Before World War I, he was living and studying in Berlin, and sent several Schoenberg scores to Edgar Bainton (q.v.) in Newcastle. Both spent most of the war in Ruhleben prisoner-of-war camp.

After WWI, Clark worked with Diaghilev for a time and spent the years 1923-36 at the BBC, first in Newcastle (1924-26), then in London, where he was responsible for many first performances and first broadcast performances.

In 1938 he met Elisabeth Lutyens, the composer and they married in 1942. They spent the war years in Newcastle. Clark founded the North East Regional Orchestra (NERO), the first professional orchestra in the region.