Harrison, Frank Llewelyn (1905–87), musicologist, organist, and composer, was born 29 September 1905 in Dublin, the second son of Alfred Francis and Florence May Harrison. He became a chorister at St Patrick's cathedral in 1912, occasionally playing the organ for cathedral services from the age of ten. From 1920 he studied at the RIAM (composition with John Larchet (qv), organ with George Hewson (qv), and piano with Michele Esposito (qv)), and was awarded the Mus.B. (1926) and Mus.D. (1929), for which he composed a setting of Psalm 19 for chorus and orchestra, from TCD.
After a brief period spent as organist of Kilkenny cathedral and third-form master at Kilkenny College, Harrison moved to Canada, where he held appointments in Nova Scotia (organist and choirmaster at Westminster presbyterian church, New Glasgow), Ottawa (organist at Knox presbyterian church, 1934–5), and Kingston (organist at St George's cathedral, 1935–40). He became resident musician and was subsequently assistant professor of music at Queen's University, Kingston, from 1935 to 1946, the final year of his tenure there being spent as a Bradley-Keeler fellow at Yale, where he studied with Paul Hindemith and Leo Schrade. From Queen's he moved to the United States, holding chairs at Colgate University, Hamilton, New York (1946–7), and at Washington University, St Louis (1947–52). Then in 1952 he crossed the Atlantic – more than likely at the invitation of Jack A. Westrup – to take up a lectureship in music at Oxford University, where he later became reader in the history of music. In 1970 he left Oxford to become professor of ethnomusicology at the University of Amsterdam; he was also a visiting professor at Yale (1958–9), Princeton (1961, 1968–9), and Utrecht (1976–9), and was elected FBA in 1965. In 1980 he visited Queen's University, Kingston, as a Queen's Quest visiting scholar, and he spent the following year as Andrew W. Mellon visiting professor at the University of Pittsburgh.
Harrison was one of the outstanding musicologists of his generation, and the breadth of his scholarly accomplishment was astonishing. His Music in medieval Britain (1958) became a standard reference text, and he also edited much early music, most notably the Eton choirbook (3 vols, 1956–61). Two further editorial projects of importance with which he became associated (from 1962) were the series Polyphonic music of the fourteenth century and Early English church music (he served as general editor of the latter project until 1972). He also promoted and guided performances of medieval music, and in the latter half of the 1960s was associated with a series of commercial recordings of this repertoire. While never forsaking his dedication to medieval music, Harrison became increasingly occupied with ethnological and sociological questions from the late 1960s, widening his field of enquiry to embrace music as a function of human behaviour. He died 29 December 1987 suddenly at Canterbury.