He taught at the Royal College of Music where he eventually became professor and the Guildhall School of Music, and was harpist to Queen Victoria. John Thomas had a brother named John Ap. Thomas, and he also played the harp. John Thomas started off by playing the triple harp which had three sets of strings and was very difficult to play. He has written many pieces for the harp that are very popular today and are used in the exam syllabus.