 During the First World War, he served as the commanding officer of the Royal Bavarian Infantry Lifeguards Regiment in France, Serbia, Romania, and at the Isonzo front.For his war service, Epp received numerous medals, of which the Pour le Mérite (29 May 1918) was the most significant.He was also knighted, being made Ritter von Epp on 25 February 1918, and received the Bavarian Military Order of Max Joseph (23 June 1916).