Matěj studied film and comparative literature at the Faculty of Arts of Charles University in Prague, followed by screenwriting and dramaturgy at Film and TV School of the Academy of Performing Arts (FAMU). He started out in television as an editor of the Víkend (Weekend) programme at TV Nova. He spent a significant part of his career working on the long-running TV soap opera Ulice (The Street), where he gradually worked as a writer of storylines and dialogues, chief writer, creative producer and supervisor. He collaborated with Czech Television as a project manager on the docusoap Paterčata (Quintuplets), contributed to the scripts for Metanol (Methanol) and Dukla 61, and the series Ochránce (The Defender) and Devadesátky (The Nineties). As a dramaturgist for Michal Reitler’s creative production group, he also worked on the film Beze stopy (Without a Trace) and the documentary Spi sladce (Sweet Dreams).