Wilhelm Moritz was a Zerstörerpilot with II./ZG 1 as the war broke out, and served as Staffelkapitän of 6./JG 77 with the rank of an Oberleutnant between November 1940 and January 1941, in both Norway and on the English Channel. After leading the operational Staffel of Jagdfliegerschule 4 more than a year, he led the formation of the new 11./JG 1 in March 1942. On September 10, 1942, he was posted to the Eastern Front, where he assumed command of 12./JG 51. The veterans of Geschwader Mölders received the new Staffelkapitän who had not scored any victories with skepticism. Moritz earned respect for the great care that he took for his subordinates, but his thirteen months on the Eastern Front did not result in any remarkable individual success in air combat. On most missions, 12./JG 51 was commanded in the air by a more skillful veteran, Leutnant Rudolf Wagner, who scored eighty-one victories before he was killed in action in December 1943. When Moritz returned to Germany to lead, he had not amassed more than twenty victories. Moritz's rise to fame began in the home defense. In April 1944, he was appointed commander of IV.(Sturm)/JG 3, and returned from almost every engagement with US heavy bombers with new victories. During the battle against US 492 Bomber Group on July 7, 1944, Moritz achieved his fortieth victory. On July 18, 1944, he was awarded with the Knight's Cross. Under Moritz's command, IV./JG 3 developed into the most successful Jagdgruppe of the home defense. On December 5, 1944, Moritz was removed from first-line service due to a complete mental and physical exhaustion. In April 1945, he returned to combat service as Gruppenkommandeur of II./JG 4. Wilhelm Moritz carried out more than 500 combat missions and was credited with 44 aerial victories.