Marek studied law at the University of Westminster in London and the University of Trnava. Since 2012, when he finished his legal practice in London, he has been practicing law in Slovakia as a partner and founder of Grand Oak Law Firm. He focuses on public procurement law, European Union law, competition law, personality protection, company law, and state aid. He also teaches at the Faculty of Law of the University of Trnava the subjects of public procurement law, state aid, and common law basics. Furthermore, he regularly contributes to several professional journals on public procurement law. In addition, he lectures at seminars focused on the same law, Euro funds, and personal data protection.