The son of a Prussian army officer, Beaulieu-Marconnay was a 16 year old high school student when the war began. A year later, he was a Leutnant in the 4th Prussian Dragoon Regiment wearing the Iron Cross, first class. "Bauli" eventually transferred to the Luftstreitkräfte, scoring his first victory by the end of May 1918. Shortly before his 20th birthday, he was given command of Jasta 19. Wounded in action on 4 October 1918, he remained with his unit, scoring two more victories before he was critically wounded in combat on 18 October 1918. Before he died at a military hospital in Arlon, Belgium, Beaulieu-Marconnay was awarded the Blue Max. He was the youngest recipient of the war to receive Prussian's highest military honor.