In the 70s, after graduating from the Academy of Performing Arts in theatre directing, he started working in the Czechoslovak television, shooting a number of TV productions. He made his debut in the cinema with the film A Cart Full of Pain / Kára plná bolesti (1985), followed by his most awarded film The Southern Mail / Južná pošta (1987), produced by the Bratislava film Studio – Koliba, and the sequel of Štefan Uhr's film ..crying for the Moon /...kone na betóne (1995). Later, he mainly devoted himself to television work, shooting film portraits for the television cycle A Dozen / Tucet, as well as several TV series, films and the fairy tale The Miraculous Nose (2013).
Párnický taught at the Academy of Performing Arts in Bratislava from 1977. In 1990 he participated in the establishment of the Film and Television Faculty, where he also served as dean in 1999-2006. In 1995, he became a professor and in 2017 he received the prize of the Minister of Culture of the Slovak Republic for his long-term extremely significant directorial contribution to audiovisual art.