Born in Trikala, a small town in central Greece, Dr. Christos Christou graduated from Aristotle University’s medical school in Thessaloniki, Greece, and holds a PhD in surgery from the Kapodestrian University of Athens. He also holds a master's degree in international health with a focus in health crisis management from the University of Athens and is a member of its faculty.

Dr. Christou specialized in general and emergency surgery in the Surgical and Transplant Unit of Evangelismos Hospital in Athens. In 2013, he moved to London, where he was a senior clinical fellow in colorectal surgery at King’s College Hospital. In 2018, he became consultant of colorectal and emergency surgery at North Middlesex University Hospital. The same year he was awarded a fellowship from the European Board of Surgery in Coloproctology.

Dr. Christou joined MSF in 2002 and held several roles. His first assignment was in Greece as a field doctor, working with migrants and refugees. He then worked as a doctor in an HIV/AIDS project in Zambia in 2004 and 2005. After a break from international work, during which he trained as a surgeon, Dr. Christou re-joined MSF in 2013 for assignments in a number of conflict zones and insecure contexts, including South Sudan, Iraq, and, most recently, Cameroon, as an emergency and trauma surgeon. He served in roles including general secretary, vice-president, and president of MSF Greece's Board of Directors, and finally, as MSF's international president from 2019 to 2025.