In 1992 Jaroslav Halíř won the international competition Concertino Praga. Shortly afterwards he was invited to participate at the trumpet seminar of the European Music Academy in Bonn led by Prof. Edward H. Tarr. Subsequently he began to give solo performances and garnered many prizes in international musical competitions. In 1995 he recorded his first solo CD.
In 1996 he became a member of the Czech Philharmonic Orchestra, where since 2001 he has been the first trumpet and also performed as a soloist in the works of A. Jolivet, J. Matěj and V. Trojan. He is one of the most sought-after studio performers of modern music, and since 2010 a member of the jazz ensemble Czech Philharmonic JazzBand.