Frank O’Sullivan is a professional guitarist, composer, and teacher based in Montreal.

After graduating from Berklee he quickly became a first-call musician in Montreal's Pop, R&B, Jazz, and Hip-Hop scenes. Maintaining a prolific and diverse career as an instrumentalist, he's worked with artists like Malika Tirolien, Dominique Fils-Aimé, Salin, and Busty & The Bass, recording and touring internationally. In 2022 he was nominated for a Juno Award in the Best Contemporary R&B Recording category, for his co-production of the song Gifted by Kallitechnis.

Since 2020, Frank has released four full-length albums of original music, and in June 2024 he opened for Al Di Meola at the Montreal International Jazz Festival. Shortly afterwards, he performed at the Rimouski Jazz Festival where he was awarded the Grand Prix de la Relève, granting him support for a tour in the summer of 2025.