Herman was born on the 23rd of June, 1893 in St Louis, Missouri, where he would attend Henrick Preparatory School and went on to enlist in the Marine Corps in July of 1914. He would be promoted to the rank of sergeant before deploying to Haiti and it was his actions during a battle with armed rebels that would earn him the Medal of Honor. The citation reads:

For extraordinary heroism and conspicuous gallantry and intrepidity in actual conflict with the enemy near GRANDE RIVIERE, Republic of Haiti, on the night of October 31st-November 1st, 1919, resulting in the death of Charlemange Peralte, the supreme bandit chief in the Republic of Haiti, and the killing and capture and dispersal of about 1200 of his outlaw followers. Second Lieutenant Hanneken not only distinguished himself by his excellent judgement and leadership, but unhesitatingly exposed himself to great personal danger, and the slightest error would have forfeited not only his life but the lives of the detachments of Gendarmerie under his command. The successful termination of his mission will undoubtedly prove of untold value to the Republic of Haiti.

Herman received his Medal of Honor in December of 1919 and was also commissioned as a second lieutenant for his actions as well. Shortly after this battle, Herman shot and killed another Haitian rebel leader that had succeeded Peralte and was awarded the Navy Cross for this. He returned to the US in 1920 and went on to serve in the Brazilian Exposition and Nicaragua, where he earned another Navy Cross for capturing a rebel leader.

For most of the 1930s, Herman spent his time in Quantico, Virginia, Mare Island, California, and Hingham, Massachusetts. During World War 2, he served with the 1st Marine Division until November of 1944. He went on to command the 2nd Infantry Training Regiment at Camp Pendleton and then the 2nd Battalion of the 7th Marine Regiment during the Guadalcanal Campaign where he would earn a Silver Star, the Legion of Merit, and a Bronze Star for his actions. Only a few year later, Herman retired from the Marine Corps as a colonel on the 1st of July, 1948. Due to his actions in combat over his 34 year long career, he received the rank of Brigadier General.

Herman Henry Hanneken died on the 23rd of August, 1986 at the age of 93 at the Veterans Affairs Hospital in LaJolla, California, and is buried in the Fort Rosecrans National Cemetery in San Diego; section C, grave 166-D.