Peter Wallensteen first came to PRIO as a visiting graduate student from Uppsala University in the Fall of 1966. This was the beginning of a life-long association. He served as an Associate Professor of Peace and Conflict Research at Uppsala University (1974–85) and then as the Dag Hammarskjöld Professor of Peace and Conflict Research (1985–2012). 

He was a member of PRIO’s Board 1987–2000. 

He has been a visiting professor at numerous universities world-wide and since 2006 has served as the Richard G Starmann Sr Research Professor for Peace Studies at the Joan B Kroc Institute of International Peace Studies, University of Notre Dame. 

An extensive interview with Peter Wallensteen by Siri Aas Rustad was published as part of the 60th Anniversary series PRIO Stories in August 2019.