Sarah McMahon began learning the cello in Nairobi at the age of ten. She subsequently moved to Dublin to study with Nora Gilleece at the Royal Irish Academy of Music. Following this, she enrolled at the Royal Academy of Music in London where she continued her studies with David Strange, Jenny Ward-Clarke and Colin Carr.

McMahon founded the Callino Quartet with whom she now has a busy performing schedule. They have collaborated with numerous composers for string quartet including Kevin Volans, Ian Wilson, Arvo Pärt, György Kurtàg, Alexander Knaifel, Aleksandra Vrebalov and Pēteris Vasks.

McMahon is passionately committed to historical performance practice and is principal cello with the Irish Baroque Orchestra and a member of Camerata Kilkenny and Ensemble Marsyas. She also receives regular invitations to play guest principal cello with the Academy of Ancient Music, Arcangelo, the Aurora orchestra and the Orchestra of the Age of Enlightenment.