Professor of geriatric medicine at the Faculty of Health and Medical Sciences at Copenhagen University, Denmark and the director of the interdisciplinary Center of Healthy Ageing, which examines the processes of getting older ranging from cells to society. He was the chair of the department of geriatric medicine at the Leiden University Medical Center in the Netherlands from 2000-2014 and the founding director of the privately funded Leyden Academy on Vitality and Ageing (2007-2014), which pursues societal innovations to improve the quality of life for older people.
Westendorp has been awarded numerous national and international grants, has published more than 600 scientific articles and has supervised over 50 PhD students of which three have already been appointed full professorships. In 2014 he published the bestseller 'Growing Older Without Feeling Old', which has been translated into nine languages. He has also been endowed with the title of Doctor Honoris Causa by the University of Newcastle in the UK (2009) and received a knighthood in the Order of the Netherlands Lion (2014).