He is regarded, along with James Morrison and Michael Coleman, as one of the finest exponents of the south Sligo fiddle style in the "golden age" of the ethnic recording industry of the 1920s and 1930s.

Killoran was born 21 September 1903 in Emlaghgissan (also spelt "Emlagation"), a townland in the civil parish of Emlaghfad near the town of Ballymote in County Sligo, Ireland.

[1] His father Patrick played the flute and his mother Mary the concertina but the young Killoran was also influenced by local fiddle master Philip O'Beirne, who had earlier tutored Michael Coleman.

[2] As a teenager, Killoran was a volunteer with the Ballymote-based 3rd Battalion of the south Sligo Brigade of the Irish Republican Army during the war for independence.

A publicity photo of Killoran's quartet c. 1928 includes button accordionist D. Casey, tenor banjo player Richard Curran and second fiddler Denis Murphy.

[6] By the next year, Killoran was performing on a weekly radio program sponsored by the Pride of Erin Ballrooms, located at the corner of Bedford and Atlantic Avenues in Brooklyn.

Uniquely among the major New York Irish musicians of the pre-World War II era, Killoran continued his musical career through the 1950s.

He issued new recordings, including duets with flute player Mike Flynn and some fiddle-and-viola sides with Paul Ryan, and led an active dance band.

Starting in 1931, Killoran made dozens of recordings as a soloist, in duets with Paddy Sweeney, and with various ensembles for Crown, Decca and other labels.