Born near Dudley in the West Midlands, Sally Harper completed her doctorate at Oxford University on music and medieval liturgy (Magdalen and Brasenose colleges) in 1989, following Bachelor and Master's degrees at Birmingham University. Following a brief period in academic administration at the University of Warwick, she began teaching at Bangor in 1991, where she discovered a passion for Wales, its people and its language. She was appointed Senior Lecturer in Music in 2006 and was for a period Director of the Centre of Advanced Welsh Music Studies and co-editor of the bilingual journal Welsh Music History / Hanes Cerddoriaeth Cymru. Sally has published widely on various aspects of music in medieval and early modern Wales as well as on medieval liturgy and church music. She is an elected Fellow of both the Learned Society of Wales and the Royal Historical Society.

Sally took early retirement from the University in 2018 to train as a priest in the Church in Wales, but continues her association with Bangor as an Honorary Research Fellow. She is also Honorary Professor in Cathedral and Sacred Music Studies at Bishop Grosseteste University, Lincoln, UK, and KTP Academic Supervisor for a research project based at Liverpool Cathedral.