He remained in the army and spent a year in the Defence Ministry (1924-25) before taking command of the elite 68th Infantry Regiment in Berlin. In January 1938 he was promoted to the rank of major general and was sent to head the Army Service Department in Silesia.
On the outbreak of the Second World War, Arnium was placed in command of the 52th Infantry Division. He took part in the invasion of Poland and France. Promoted to the rank of lieutenant general, he served under General Heinz Guderian during Operation Barbarossa. However, he was seriously wounded at Stolpce on June 24, 1941. After making a full recovery, he took part in the encirclement of Kiev and the capture of Bryansk.
In November 1942, Arnim was promoted to general and placed in command of the 5th Panzer Army in Tunisia. After General Erwin Rommel left in March 1943, Arnim became head of the German Army in Africa but was unable to halt the Allied advance and, on May 11, 1943, the Axis forces surrendered Tunisia. The following day Arnim was captured by the Allies.
The second highest-ranking German prisoner of war (after Rudolf Hess), he was held in Britain until 1947. Hans von Arnim returned to Germany where he lived until his death on September 1, 1962.