John F. Larchet was born in Dublin. He studied at the Royal Irish Academy of Music where his teachers included Michele Esposito. He received his MusB in 1915 from Dublin University and completed his MusD in 1917. Larchet was Director of Music at the Abbey Theatre from 1907 to 1934 and was professor of harmony and counterpoint at the Royal Irish Academy of Music from 1920 to 1955. He was also professor of music at University College Dublin from 1921 to 1958.
As a teacher, Larchet was influential in developing a school of Irish composers, many of whom went on to become important figures in Irish composition. Irish traditional music was a source for many of his works and his output includes several choral, orchestral and vocal works.