Graduated in 1991 from the Department of Architecture, Institut Teknologi Bandung (ITB). In 1999 he completed a Doktor-Ingenieur (Dr.-Ing.) degree in urban design from the Fachbereich Stadt- & Landschaftsplanung, Universitaet Gesamthochschule Kassel, Germany. He was a former chair of graduate program in Architecture and Urban Design at the faculty from Nov. 2009 – Dec .2010. He has held visiting scholar position at the Faculty of Architecture, University of Applied Sciences, Germany in 2008-2009. Since 2011 he has been in charge for the Vice Dean for Academic Affairs, School of Architecture, Planning and Policy Development. In 2013 he becomes the chairman of Architectural Design Research Group, and has been actively involved with the Architectural and Urban Heritage Conservation, Site Planning Studio, Architectural Design Studio, Urban Design Studio. His main research fields are architectural design and urban heritage conservation in Indonesia. Through his teaching, research and professional engagements, he has contributed to the study of architectural conservation, urban heritage conservation, and urban design in Indonesia. Besides, Widjaja is assessor of National Accreditation Agency of Higher Education, and also an honorary member of Indonesian Astronomy Society.