Ekéus was High Commissioner on National Minorities at the OSCE from 2001 till 2007, as well as on the board of directors for the Nuclear Threat Initiative (NTI). Since 2005, Ekéus has been a Commissioner of the International Commission on Missing Persons (ICMP). He is also Member of the Supervisory Council of the International Luxembourg Forum on Preventing Nuclear Catastrophe, a not-for-profit organisation uniting leading experts on non-proliferation of nuclear weapons, materials and delivery vehicles.