Thomas began his professional career at Queen's University Belfast in 1973.
In the late 1970s and early 1980s, Thomas conducted concerts with the Ulster Orchestra and contemporary music ensembles such as Lontano.
He was subsequently elected a Fellow of Gresham College (2006–09) and Emeritus Professor in 2009.
Adrian Thomas is a specialist on Polish music and has published widely on the topic.
He has given research papers, public talks and broadcasts in Europe, the USA and Australia.