As an organist Isham held several positions including deputy to Croft in London, organist of St. Anne’s, Soho, St. Andrew’s, Holborn, and St. Margaret’s, Westminster. He was a graduate of Oxford having a Bachelors in Music and made up several anthems two which were within Croft’s “Divine Tranquility.” With William Morley Isham collaborated on the collection of tracks and included his personal “Bury delights my roving attention.”