Josef “Pips” Priller was born on 27 July 1915 at Ingolstadt in Bayern. In 1935, Fahnenjunker Priller was serving in Infanterieregiment 19. Oberfähnrich Priller transferred to the Luftwaffe and began his flying training at Salzwedel in October 1936. 

On 1 April 1937, Leutnant Priller was posted to I./JG 135. In November 1938 the unit was redesignated I./JG 233 and again on 1 May 1939 to I./JG 51. In July 1939, he was serving with I./JG 71 which was to be redesignated II./JG 51 in October 1939. On 1 October 1939, Priller was appointed Staffelkapitän of 6./JG 51. He gained his first victories on 28 May 1940 over Dunkirk in aerial combat with RAF fighters. He claimed six victories during the French campaign, including his 6th on 25 June, when he shot down a RAF Spitfire fighter near Desvres.

By the end of August his victory total stood at 15. On 17 October, Oberleutnant Priller claimed his 20th victory resulting in the award of the Ritterkreuz on 19 October. He claimed at least fourteen victories in the Battle of Britain. On 20 November 1940, Priller was transferred as Staffelkapitän to 1./JG 26, succeeding Oberleutnant Eberhard Henrici (7 victories) who had been lost in aerial combat over the Channel three days previously.

Despite much combat with the British, Priller was unable to add to his score before the end of the year. That winter, JG 26 was withdrawn from the Channel front back to Germany for a rest. On his return to the Channel Priller enjoyed a remarkable run of victories between 16 June and 11 July 1941 shooting down 19 RAF aircraft, including 17 Spitfire fighters, to bring his victory total to 39. On 14 July, Priller shot down his 40th victim. He was awarded the Eichenlaub (Nr 28) on 19 October for 41 victories. Hauptmann Priller became Gruppenkommandeur of III./JG 26 on 6 December 1941. By the end of 1941 Priller’s score stood at 58. He recorded his 60th victory on 27 March 1942 and his 70th victory on 5 May.