David Simon enjoys a diverse career of music teaching and performing. He is a music instructor at St. Michael's Choir School and runs an online private studio which includes students from coast to coast in North America. One of the few instructors in Canada of organ improvisation, he also teaches music theory, history, analysis, and piano. As an organist, he has played recitals and accompanied choir tours across North America, Europe, the U.K., and Russia and has given premieres with the Toronto and New Haven Symphony Orchestras. An experienced liturgical musician, he plays for weekly masses at St. Michael's Cathedral-Basilica.

David's achievement in organ performance and improvisation have been recognized in competition and examination. In 2019, he won first prize in the Royal Canadian College of Organists national competition, and won first prize and audience prize in the University of Michigan international organ improvisation competition. He is a Fellow of the Royal Canadian College of Organists (FRCCO) and received the Healey Willan Prize for top national achievement on the Fellowship examination. David is completing his Doctor of Musical Arts degree at Yale University, having studied with Thomas Murray and Jeff Brillhart.