In London, Kœnig joined General Charles de Gaulle and was promoted to colonel. He became chief of staff in the first divisions of the Free French Forces. In 1941, he served in the campaigns in Syria and Lebanon. He was later promoted to general and took command of the First French Brigade in Egypt. His unit of 3700 men held ground against five Axis divisions (c. 37,000 men) for 16 days at the Battle of Bir Hakeim until they were ordered to evacuate on 11 June 1942. General de Gaulle said to Kœnig: "Hear and tell your troops: the whole of France is watching you, you are our pride."