The Mk. IX replaced the Mk. V in June 1942 and on September 12, 1942 a Mk. IX brought down a Ju-86R flying at 43,000 feet. Another major achievement of the Mk. IX took place on October 5, 1944 when 401 Squadron became the first allied aircraft to shoot down an Me-262 jet. Even with the arrival of the Griffon powered Mk. XIV the Mk. IX continued in service until the end of WWII. There were 5,665 Mk. IX Spitfires and its variants produced.
1,328 British Spitfire Mk. IXs were supplied to the Soviets during WWII. One of these aircraft was PT879, built at the Vickers Armstrong Factory and arriving in Murmansk in October 1944 assigned to the 2nd Squadron, 767th Regiment and 122nd Division of the Russian Air Force. On May 18, 1945 PT879 was involved in a training dogfight. The aircraft only had 18 hours and 29 minutes of flying time when another Spitfire cut off its tail. The pilot managed to bail out. The wreckage was later recovered and eventually restored by the Hangar 11 team.