Karl Bolle read economics at Oxford University in 1912. Returning to Germany, he enlisted as a Leutnant in the 7th von Seydlitz Kürassier Regiment and was sent to fight on the Western Front. In 1915 his regiment was transferred to the Eastern Front and by the end of the year, Bolle was awarded the Iron Cross, second class. He transferred to the air service in February 1916 and received training at Valenciennes before being posted to KG 4 in July 1916. At the end of the year he was reassigned to Kampfstaffel 23, flying with Lothar von Richthofen as his observer, and was awarded the 2nd Class Knight's Cross of the Friedrich Order. Wounded in October 1916, Bolle recovered and was sent to Jastaschule in early 1917. In July 1917 he was posted to Jasta 28 and scored 5 victories before assuming command of Jasta 2 as an Oberleutnant on 20 February 1918. In August, having downed 28 opponents, he was promoted to Rittmeister and received the Military Merit Cross, the Royal House Order of Hohenzollern and the Blue Max. Bolle finished the war with 36 victories. Post-war he became a flying instructor and served as Director of the German Transportation School in the 1920s. During World War II he was an advisor to the Luftwaffe.