Sturmbannführer (Major) was a member of the Waffen-SS branch during World War II. Buchner was awarded the Knight's Cross of the for extreme battlefield bravery and also received the very rare Close Combat Clasp in Gold.

Out of the 13-15 million German servicemen of all branches during WWII, only 631 men were awarded the golden Close Combat Clasp and out of those, only 98 soldiers were simultaneously holders of the Knight's Cross. Buchner was the 4th soldier to receive this prestigious Clasp, recording over 60 days spent in close quarter combat. In July and August 1943 alone, he recorded 20 days of hand-to-hand combat. Sturmbannführer Buchner is considered to belong to the "Aces of Infantry."

Buchner was not a staunch Nazi and against Hitler's policy, he never joined the Nazi party. He joined the SS when he was 20 years old because he believed that the Waffen-SS was the elite of the elite. He attended officer candidate school but failed the first attempt and barely passed his second. Although Buchner performed poorly in the classroom, he was still promoted quickly after being commissioned, a testament to his excellent service with SS-Division "Totenkopf". He first saw combat in France but it was the early days of Operation Barbarrossa, the invasion of the Soviet Union, that he saw serious warfare. He engaged in numerous house-to-house and heavy urban close quarter fighting. During the encirclement of Demyansk he was again involved in intense close combat and wounded by shrapnel. He recovered quickly, however, and returned to his unit.

With his promotion to Sturmbannführer he became commander of 3rd Battalion, 5th SS-Panzer Grenadier Regiment, 3rd SS-Panzer Division. Even as a battalion commander he led by example and from the front. Buchner saw it as an inspiration to his men when their commander was with them in the thick of the fighting. He earned the Knight's Cross when he led an infantry attack without heavy armour support on a well fortified Soviet position. His unit took on the objective with minimal casualties due to his skilled leadership.

He was also awarded the silver Tank Destruction Badge for when he had single-handedly destroyed an enemy tank by using a single hand-held weapon. Further awards included the in Gold, the Infantry Assault Badge and the in Gold (indicating he was wounded five times or more).

Sturmbannführer Buchner was killed in action in the Polish Modlin province, west of Warsaw, on 17 November 1944 by a fatal wound. He was hit in the back (which he despised most) by shrapnel. He was only 27 years old.