Ljungdahl was born on 7 August 1897 in Lund, Sweden, the son of merchant August Ljungdahl and his wife Clara and brother of Karl-Gustaf Ljungdahl, the CEO of ÅF. He became an officer at the South Scania Infantry Regiment in 1918 and was trained as a pilot at Malmslätt from 1921 to 1923. Ljungdahl also attended the Royal Central Gymnastics Institute from 1922 to 1924, the Royal Swedish Army Staff College from 1924 to 1926 and the Royal Swedish Naval Staff College from 1926 to 1927. He served as captain of the General Staff in 1930 and as teacher at the Royal Swedish Army Staff College from 1930 to 1937. Ljungdahl was military attaché and air attaché in London from 1935 to 1936 and was promoted to major in the Swedish Air Force the same year. He was head of the Education Department of the Air Staff from 1936 to 1939 when he was promoted to lieutenant colonel. Ljungdahl was wing commander of the Västmanland Air Force Wing from 1939 to 1942 and was promoted to colonel in 1940. He was then Chief of the Air Staff from 1942 to 1947 and was promoted to major general in 1943. Ljungdahl was commanding officer of the Third Air Group from 1947 to 1954 when he was promoted to lieutenant general. In 1954 he was appointed Chief of the Air Force. During Ljungdahl's time as Chief of the Air Force began the necessary modernization and expansion of including base and combat management systems. The Air Force began to bring balance and thus became a more homogenous and enduring force. He retired in 1960 and was then promoted to full general. Ljungdahl conducted his farewell flight as Chief of the Air Force in a J 28 Vampire. During his career, Ljungdahl was also an expert in the 1930 Defense Commission and a member of the 1931 and the 1933 Air Commission as well as the Civil Aviation Board in 1945. He was a board member of the pension insurance company Valand-Pensionsbolaget and chairman of the board of Ostermans Aero AB. Ljungdahl became a member of the Royal Swedish Academy of War Sciences in 1943 and was its president from 1955 to 1957. After retiring from the military, Ljungdahl devoted his time to studies and received a Bachelor of Arts degree in 1965, a Licentiate of Philosophy degree in 1968, a Doctor of Philosophy degree in 1970 and a Bachelor of Theology degree in 1975.
Personal life
In 1938 he married Ruth Hallert, the daughter of managing director Axel Johansson and his wife. Ljungdahl was the father of Birgitta. Ljungdahl died on 12 April 1995 in Stockholm and was buried at Norra begravningsplatsen in Stockholm.
