Career
He played for the Czechoslovakian Republic, for which he played 38 matches and scored 1 goal. Horňák played for several clubs, including TJ Gottwaldov, RH Cheb, Sparta Prague (most of his career) and LASK Linz (Austria). He later was the assistant coach in the Czechoslovakian club FK Teplice.
He took over as manager of Football Club Graffin Vlašim in April 2013, but only stayed until the end of the calendar year before being replaced by Vlastimil Petržela.