In 1969, Priestley moved to London and began playing piano with bands led by Tony Faulkner and Alan Cohen.

Priestley helped transcribe Duke Ellington's Black, Brown and Beige,[2] and Creole Rhapsody for Cohen, and formed his own Special Septet featuring Digby Fairweather and Don Rendell.

His compositions include Blooz For Dook (published in his 1986 book Jazz Piano 4), The Whole Thing (recorded by the National Youth Jazz Orchestra in 1997) and Jamming With Jools (a 1998 examination piece for the Associated Board of Royal Schools of Music, based on a live broadcast with Jools Holland).

Priestley has also written biographies of Charles Mingus, John Coltrane and Charlie Parker,[2] as well as the book Jazz on Record: A History.

Since 2006, Priestley has lived in Tralee, Ireland, where he continues playing the piano and presents a show on Radio Kerry.