Thomas Agerfeldt Olesen was educated as a cellist at the Royal Academy of Music, Aarhus. As a cellist he has performed with a number of Danish ensembles such as The Jutland Ensemble, Ensemble 2000 and Trio TSIAJ of which he is a permanent member.
Thomas Agerfeldt Olesen studied composing with a.o. Poul Ruders, and in 1997 he was awarded the three-year scholarship of the Danish Arts Foundation. He has composed for Danish and international ensembles such as Århus Sinfonietta, Ensemble Figura, Moscow Chamber Orchestra, The European Chamber Orchestra and Ensemble 2000.