He was born in Würzburg, Germany. Educated at Cadet School in Munich, he graduated in 1910 and joined the army as an artillery officer. During WW I he was a battery officer and served on the Western Front 1914-16, twice being wounded. In 1917 he served briefly on the Eastern front before returning to the west as a staff officer. After the war Jodl remained in the armed forces and joined the Versailles-limited Reichswehr. He became acquainted with Adolf Hitler in 1923. He was regularly promoted and by 1935 he was Abteilung Landesverteidgung im Oberkommando der Wehrmacht (Chief of the National Defense Section in the High Command of the Armed Forces). In the build-up to war he was assigned as a Artillerie Kommandeur of the 44th Division from October 1938 to August 1939 during the Anschluss, but from then until the end of the war he was Chef des Wehrmachtsführungstabes in OKW (Chief of Operation Staff of the High Command of the Armed Forces). Jodl was a key figure in German military operations from then on, supplying advice and technical information to Hitler. He was injured in the July Plot against Hitler.
Generaloberst Jodl signed the unconditional surrender on May 7, 1945 in Reims as the representative for Karl Doenitz. He was then arrested and transferred to Flensburg POW camp and later put before the International Military Tribunal at the Nuremberg Trials. He was accused of conspiracy to commit crimes against peace; planning, initiating and waging wars of aggression; war-crimes; and crimes against humanity. He pleaded not guilty "before God, before history and my people". Found guilty on all four charges, he was hanged.
In 1953 a German arbitration board posthumously acquitted Jodl of all charges.