Early life

Hamann joined the Schwerin 89th Grenadier Regiment in 16 July 1901. He was promoted to corporal on 27 January 1904 and to Unteroffizier

Unteroffizier

Unteroffizier is both a specific military rank as well as a collective term for non-commissioned officers of the German military that has existed since the 19th century. The rank existed as a title as early as the 17th century with the first widespread usage occurring in the Bavarian Army of the...

 at 27 January the following year. Hamann became a Sergeant on 3 March 1908, and a Feldwebel

Feldwebel

Feldwebel is a German military rank which has existed since at least the 18th century with usage as a title dating to the Middle Ages. The word Feldwebel is usually translated as sergeant being rated OR-6 in the NATO rank comparison scale, equivalent to the British Army Sergeant and the US Army...

 at 1 October 1911. In 1914, during the first year of WWI, he was twice awarded the Iron Cross

Iron Cross

The Iron Cross is a cross symbol typically in black with a white or silver outline that originated after 1219 when the Kingdom of Jerusalem granted the Teutonic Order the right to combine the Teutonic Black Cross placed above a silver Cross of Jerusalem....

. At 7 August 1916, he was promoted to a Warrant Officer and appointed as a platoon commander.

Interwar years

At 7 August 1919, Hamann was commissioned as a second Lieutenant and transferred to the 17th Infantry Regiment of the newly-created Reichswehr

Reichswehr

The Reichswehr formed the military organisation of Germany from 1919 until 1935, when it was renamed the Wehrmacht ....

, where he served as the commander's adjutant. At 1 October 1920, he was assigned to the 6th Infantry Regiment as a company's operations officer. On 15 January 1921 he was promoted to Lieutenant, and on 1 April 1923 he was given the rank of a Captain and the command over a company.

At 1 July 1933, he was promoted to Major and assigned to staff duty. From 1 July to 1 October 1934, he commanded the Flensburg

Flensburg

Flensburg is an independent town in the north of the German state of Schleswig-Holstein. Flensburg is the centre of the region of Southern Schleswig...

 Infantry Battalion. Afterwards, he headed the 3rd Battalion of the Neumünster

Neumünster

Neumünster is an independent town in Schleswig-Holstein, Germany, which has a total of four independent towns.-Current Situation:Neumünster station is major railway junction with lines running in six directions, including the important Hamburg-Altona–Kiel and Neumünster–Flensburg lines.Near...

 Regiment, and was transferred to the 46th Regiment on 15 October 1935, in which he commanded the 3rd Battalion, as well. At 1 March 1936 he was promoted to Lieutenant Colonel. From 1 February 1937 until 3 January 1939, he commanded the Stablak training area in East Prussia

East Prussia

East Prussia is the main part of the region of Prussia along the southeastern Baltic Coast from the 13th century to the end of World War II in May 1945. From 1772–1829 and 1878–1945, the Province of East Prussia was part of the German state of Prussia. The capital city was Königsberg.East Prussia...

. While holding that office, he was promoted to Colonel on 1 August 1938. From January to 1 September 1939, he commanded the Tiborlager training area near Schwiebus.

WWII

Immediately after the German invasion of Poland, Hamann was given the command of a frontier defense zone on the Polish border, which he held until 8 January 1940. Afterwards, he commanded the 3rd Reserve Infantry Battalion until 25 July 1941.
From 4 August until 14 January the following year, he headed the 239 Infantry Division's 327 Regiment. After the division was dissolved, he was transferred to the Führerreserve

Führerreserve

The Führerreserve was a section set up in 1939 in many army units, in which high officers waited for a new assignment. Also, troublesome officers were sometimes shifted into the Führerreserve, since the High Command believed that they would be less dangerous there...

, where he remained until 1 April. Then he was posted as the commander of the 370th Division's 666th Regiment, stationed at Reims

Reims

Reims , a city in the Champagne-Ardenne region of France, lies east-northeast of Paris. Founded by the Gauls, it became a major city during the period of the Roman Empire....

, in the French Zone occupée

Zone occupée

The zone occupée was the area of France where German occupying troops were deployed during the Second World War after the signature of the Second Armistice at Compiègne...

. He held the office for only six weeks and was recalled to the reserve on 14 May.

On 1 June 1942, he was promoted to Major General and sent to serve as the governor of Oryol

Oryol

Oryol or Orel is a city and the administrative center of Oryol Oblast, Russia, located on the Oka River, approximately south-southwest of Moscow...

, in the German-occupied area of the Soviet Union. During the Battle of Kursk

Battle of Kursk

The Battle of Kursk took place when German and Soviet forces confronted each other on the Eastern Front during World War II in the vicinity of the city of Kursk, in the Soviet Union in July and August 1943. It remains both the largest series of armored clashes, including the Battle of Prokhorovka,...

, while still commandnat of Oryol, he was the chief of Gruppe Hamann - a support formation which consisted mainly of the 3rd Brandendburg Regiment and existed from 20 July to 1 August as part of General Lothar Rendulic

Lothar Rendulic

Generaloberst Lothar Rendulic was an Austro-Hungarian and Austrian Army officer of Croatian origin who served as a German general during World War II. He commanded the 14. Infanterie-Division, 52. Infanterie-Division, XXXV Armeekorps, 2. Panzer-Armee, 20...

's XXXV Corps. On 4 August, after Oryol's liberation in Operation Kutuzov

Operation Kutuzov

Operation Kutuzov was a military operation by the Red Army in its fight against the German Wehrmacht during World War II. It was named after Mikhail Illarionovich Kutuzov, the Tsarist General credited with saving Russia from defeat during the invasion by Napoleon in 1812.The Operation began on 12...

, he was made commandant of Bryansk

Bryansk

Bryansk is a city and the administrative center of Bryansk Oblast, Russia, located southwest of Moscow. Population: -History:The first written mention of Bryansk was in 1146, in the Hypatian Codex, as Debryansk...

. When it was retaken by the Red Army

Red Army

The Workers' and Peasants' Red Army started out as the Soviet Union's revolutionary communist combat groups during the Russian Civil War of 1918-1922. It grew into the national army of the Soviet Union. By the 1930s the Red Army was among the largest armies in history.The "Red Army" name refers to...

 on 17 September, he became the governor of Bobruisk, in Belorussia.

On 1 June 1944, an order to promote Hamann to Lieutenant General was issued, though it was not implemented. At 20 June, he was given command of the 383rd Infantry Division, replacing General Edmund Hoffmeister

Edmund Hoffmeister

Edmund Hoffmeister was an officer in the German Army, mainly notable for his service in the Wehrmacht Heer during World War II.Hoffmeister's military service began in 1914 in the Imperial German army...

, while retaining his position as commandat of what was now the Fortified Area (Fester Platz) Bobruisk.

Capture and trial

On 22 June 1944, the Soviets initiated Operation Bagration. The Red Army soon overwhelmed the German forces stationed near Bobruisk, and encircled the city on the 27th. At 28 June 1944, Hamann - along with the rest of the Bobruisk garrison - was taken prisoner. On 17 July, he was paraded through the streets of Moscow with 50,000 other captured German soldiers. He was officially promoted to Lieutenant General while in Soviet captivity, on 20 August 1944.

At 30 December 1945, a Soviet court convicted him of war crimes against the civilian populations of Bryansk and Bobruisk. Hamann was sentenced to death, and hanged on the same day.