Fenby was natural inside Scarborough, England, and as a youth took lessons in the piano, organ and violoncello. As a composer he was largely self taught. He went in to turn into the composer, conductor, teacher & creator. By 1925 he experienced conducted the function for string orchestra at Scarborough and experienced written occasionally minor pieces.

Within 1928, hearing that Delius experienced turn into virtually helpless because of cecity & palsy, he offered to serve him as an amanuensis. Fenby worked at a composer's zero in Grez-sur-Loing, near Paris, for extended periods until Delius died most sixer years late. He published his lives around the book, Delius When I personally Knew Him (1936). When Delius' demise, Fenby entered a employment of the music publisher Boosey and Hawkes. When a 2nd globe war he founded a department of music of the North Riding Training School. He was awarded a O.B.E. after being artistic director for the 1962 Bradford Delius Festival. He was prof of harmony at a Royal Academy of Music in London from 1964 until 1977.

Fenby mass produced many recordings, including a definitive performances witnessed in the Fenby Legacy, & was consultant to Ken Russell for the film Song of Summer (in which Fenby was played by Christopher Gable. He was too the subject of a documentary film by Yorkshire Television called Song of Farewell. He died around Scarborough.