Born in Zagreb, Croatia, Robert is a graduate from the Faculty of Architecture, University of Zagreb. From 1999 to 2004, he was a Project Leader at APZ inženjering“-Zagreb. In 2004, he established the authorized architecture planning office of Robert Križnjak. Since 2005, he has been working with Martina Križnjak, (M. Arch.).

The Architectural Studio Križnjak is formed by a team of creative architects whose areas of interest and activities include architectural and interior design as well as construction site supervision.  These architects, forming a team, seek to achieve the harmony between the architectural design and the final realization. The main goal is to achieve architecture that combines aesthetics and functionality, integrating into its community. They are the founders and heads of interior section of Društvo arhitekata Zagreb (Zagreb Society of Architects).

Robert also co-operates with the daily paper Jutarnji list.