Feldwebel Matoni was assigned to 9./Jagdgeschwader 27 (JG 27—27th Fighter Wing) in the summer of 1940 and his first claim, a Hawker Hurricane followed on 30 September.

[2] He was badly wounded in aerial combat resulting in a lengthy convalescence, following which he served as an instructor with Jagdgruppe West from October 1942 to February 1943.

On 31 August, Oberleutnant Matoni's Focke-Wulf Fw 190 A-6 (Werknummer 530118—factory number) was hit and he was wounded by return fire from United States Army Air Forces (USAAF) Boeing B-17 Flying Fortress bombers resulting in a forced landing at Montdidier.

On 15 August 1944, Hauptmann Matoni was appointed Gruppenkommandeur (group commander) of I. Gruppe of Jagdgeschwader 11 (JG 11—11th Fighter Wing).

The Gruppe had just relocated to an airfield at Dammartin-en-Goële and had been augmented by a fourth Saffel following a period of rest an replenishment in Germany.

[6] In September, he was transferred and appointed Gruppenkommandeur of I. Gruppe of JG 2, replacing Hauptmann Erich Hohagen who had been injured in combat.

[7] On 5 December, Matoni was so seriously injured in a takeoff accident at Merzhausen due to engine failure of his Fw 190.

Just three years before his death, among other guests Matoni appeared on the British television show This Is Your Life on the 8 May 1985, the 40th anniversary of the German capitulation.

Matoni's presence owed to a British media-created legend that Johnson personally challenged the German to a duel over Normandy.