Philip Shannon took his first degree from Oxford, where he was a mathematics scholar at the age of 16. Encouraged by Roger Vignoles to follow his first love, piano accompaniment, he entered the Guildhall School of Music in 1985 for advanced studies under Paul Hamburger and Gordon Back. After winning all the accompaniment prizes in his first year, he was awarded a scholarship to study vocal repertoire with Graham Johnson.  

He has been active in every capacity as a musician: as repetiteur with experience at English National Opera and numerous smaller companies; as organist at the church of St Anne's, Soho; as vocal and instrumental coach at the Guildhall School of Music and Drama; as broadcaster on Radio 3 with the violinist Leo Payne, with whom he was a joint winner of the National Federation of Music Societies competition; as pianist for both the London Symphony and London Philharmonic Orchestras, and continuo player with the London Mozart Players. For television he has worked on the Lesley Garrett Show.

In 1997 he received an Honorary Fellowship from the Guild of Musicians and Singers.