With the philharmonic orchestra Karol Petróczi attended many different tours and regularly performed as its soloist. In chamber music he for a long time cooperated with pianist Anna Ličková. As concert master he has worked also abroad – Cairo Symphony (Egypt), Camerata Helvetica, and Orquesta Symfonica de Asturias (Spain).
Significant is his work is the field of choir conducting. He was the longtime choirmaster of Košice Teachers' Choir (cooperation lasts to the present) and choir Collegium Technicum, which under his leadership has received important awards and recognition at international competitions and festivals.
He is a respected pedagogue at the Conservatory in Košice and his significant educational achievements rank him among the top Slovak violin professors. He also taught at Tokyo University in Japan.