[3] Leaving British Guiana at the age of 20, he had settled in England by 1931, and subsequently worked in other parts of Europe but lived most of his later years in London.

[3] In 1925, Dunbar moved to Paris and between 1927 and 1929 attended the Sorbonne, where he studied conducting with Philippe Gaubert, composition with Paul Vidal, and the clarinet with Louis Cahuzac.

[5] He wrote columns as a technical expert in the Melody Maker for seven years[4] and in 1939 published his Treatise on the Clarinet (Boehm System), which became a standard text about the instrument.

[10] His ballet, Dance of the Twenty-First Century, written for Cambridge University's Footlights Club, was premiered in the US in 1938 on an NBC broadcast.

[12] In September 1945 he conducted the Berlin Philharmonic at the invitation of music director Leo Borchard, performing William Grant Still's Afro-American Symphony before Allied servicemen.

"[16] He championed the music of other black composers, particularly the African-American Still, alongside whom he had played in the Harlem Orchestra in the 1920s,[17] and the autograph of Still's Festive Overture of 1944 is dedicated "To my dear friend, Rudolph Dunbar".

He became London correspondent for the Associated Negro Press news service in 1932, and in 1936 reported for them on debates in the House of Commons on the Italian invasion of Ethiopia.