Killen has close to 30 years of global humanitarian leadership experience, most of this focused on food security & livelihoods programming in Africa, Asia, Eastern Europe and the Middle East. He is currently the COO for JAM International, based in Johannesburg, South Africa. Until January 2020, he was the Country Director of JAM South Sudan & Uganda. Killen also worked as regional Head of Food Security & Livelihoods at the Danish Refugee Council (Eastern Africa and Yemen). He worked for UN agency WFP as the national Food Security & Livelihood Cluster Coordinator. Killen was the global Head of Food Assistance and Nutrition Unit at Plan International headquarters in London UK. Prior to that, he provided leadership as the Head of Mission and Response Director for World Vision’s Syria refugee response in Jordan and also in the Horn of Africa. He was also the global Director of World Vision's Food Aid Management & Emergency Response Unit based in Johannesburg South Africa. In World Vision and Plan International Killen participated as part of surge capacity in some of the largest humanitarian responses in Indonesia, the Horn of Africa, Philippines, Haiti, Niger, Syria etc