After graduation, he won a Peter Moores Foundation scholarship (1985) and joined the Royal Northern College of Music to study voice with the baritone John Cameron where he developed a love for lieder and German poetry.
His money ran out before he could finish his four-month term there, but Rudolf Knoll, a teacher at the Salzburg Mozarteum, gave him private lessons for free.
[2] In 1989, Keenlyside joined the roster of Scottish Opera, where he stayed until 1994, performing as, among other roles, Marcello (La bohème), Danilo (The Merry Widow), Harlequin (Ariadne auf Naxos), Guglielmo (Così fan tutte), Figaro (Barber of Seville), Billy Budd (Billy Budd), Papageno (Zauberflöte) and Belcore (L'elisir d'amore).
Keenlyside sang in the world premieres of two 21st-century operas, creating the roles of Prospero in Thomas Adès' The Tempest in 2004, and Winston Smith in Lorin Maazel's 1984 in 2005.
[5] In 2010 Keenlyside sang the role of Rodrigo in a new production of Don Carlo at the Metropolitan Opera opposite Roberto Alagna to critical acclaim.