Competing in three Summer Olympics, he won a silver in the C-1 500 m event at Atlanta in 1996.

An out-and-out sprinter, his preferred distance was in fact the 200 m (not included on the Olympic schedule).

The following year he won the silver medal in Szeged, Hungary.

Kňazovický also earned a bronze in the C-4 500 m event at the 1994 World championships in Mexico City.

Kňazovický is now the coach of the current Slovakian number one Marián Ostrčil.