He comes from a family of scriptwriters, graduated in dramaturgy and scriptwriting, and made his debut with two music documentary films – about the band Visací zámek (1993) and the band Mňága a Žďorp (1996). In 1997 he made the film Knoflíkáři (Buttoners), in which the theme of isolation and alienation plays a central role. For David Ondříček he wrote the script for the film Samotáři (Loners, 2000), which became the testimony of a single (solitary) generation, which was followed by a music documentary about Jaromír Nohavice, Rok ďábla (The Year of the Devil, 2002), for which Zelenka was awarded the Crystal Globe at the Karlovy Vary film festival. He adapted his own Příběhy obyčejného šílenství for the theatre and cinema (2005), and this was followed by Karamazovi (The Karamazov Brothers, 2008), again a theatre and film project with actors from the Dejvice theatre. His latest film project is Ztraceni v Mnichově (Lost in Munich).
His debut work as an author was the book Nové náboženství Kurta Vonneguta (Kurt Vonnegut’s New Religion, HaH, 1992) – Vonnegut as well as Bukowski are among Zelenka’s favourite authors. In the book he arranged quotations and notes from his reading of Vonnegut, which can also serve as a guide to the writer’s work.
Also published in book form were his scripts for Knoflíkáři (Mladá fronta, 1998) and Příběhy obyčejného šílenství (Větrné mlýny, 2005). He published the play Teremin (Theremin, SaD, 2006), which was staged by the Dejvice theatre. This is the darkly comic story of the Russian inventor Theremin, who comes to the United States with his thereminophone to promote communism – Zelenka is a well-known opponent of the Communist Party. The text of the play Ohrožené druhy (Endangered Species, SaD, 2011) depicts the boundaries of friendships, comments on the media reality and advertising practices and criticizes the methods of multinational pharmaceutical companies. In 2011 Zelenka staged it at the National Theatre’s New Stage.
In 2014 the publishers Akropolis brought out a collection of all of Zelenka’s stage plays under the collective title Obyčejná šílenství (Ordinary Madness, Theatre Plays 2001 – 2012).
