LeGassick trained at York University and has worked professionally as a pianist, composer, producer, and lecturer. As a pianist, he specializes in late 20th century solo repertoire and chamber music.
LeGassick has been involved in commercial music since attending sixth-form college. He has played keyboards for Madonna, R.E.M., and Blur, but since 1999 has been more active as a producer, picking up over a dozen gold and platinum discs along the way.
He is currently completing a PhD at Surrey University on the early music of Anton Webern. He has lectured at Dartington College of Arts and also at the Guildhall School of Music and Drama. LeGassick now teaches at the Yehudi Menuhin School for young musicians.