Born Bangor North Wales October 25th 1895.
Studied with Dr Roland Rogers at Bangor Cathedral becoming assistant organist at age of 13 in 1909. Left to study with Granville Bantock in Birmingham in 1916. Studied at Royal College of Music with Holst, Vaughan Williams and Morris. Worked as BBC pianist during 20s and 30s. Accompanist to City of Birmingham Orchestra from 1919, working with Appleby Matthew's Adrian Boult and Leslie Heward. Mulllinars songs were performed at the Proms from 1918 to 1924. He worked as professor of accompaniment at RCM until 1965
Dedicatee of Vaughan Williams Sixth Symphony.
Died at Kew in 1973.