[1] His father, Tom Glackin, was an officer with the Garda Síochána in Dublin and a notable fiddle player who instilled in Paddy a deep interest and love of the music of his native County Donegal, and taught him and his brothers Kevin and Seamus to play the instrument.

[3] His playing style, however, was developed more informally at home, where his father organized regular Wednesday afternoon music sessions with many musicians, including Seamus Carroll, Larry Redigan and Frank O'Higgins.

[1] Paddy's musical influences, however, are not limited to Donegal; he also cites fiddlers such as John Kelly, Tommy Potts and Padraig O'Keeffe as important in shaping his overall approach.

During his college years in Dublin, the city's vibrant traditional music scene offered Glackin opportunities to meet fellow players his own age and perform a wide variety of venues.

[3] He became friends accordionist Tony MacMahon, flautist Matt Molloy, uilleann piper Paddy Keenan, brother and sister Mícheál Ó Domhnaill and Tríona Ní Dhomhnaill, and Dónal Lunny—all of whom would go on to prominent careers in Irish traditional music.

More recently, Glackin recorded the duet album Seidean Si (1995) with piper Robbie Hannon, and Reprise (2001) with his former Bothy Band colleague, the late Mícheál Ó Domhnaill.