He did not destroy the most enemy tanks of any German tank commander
On numerous websites and in books and magazine articles Wittmann is described as the most successful German tank commander, based on his personal destruction of the most enemy tanks during the war. Three German commanders were credited with destroying more enemy tanks than Wittmann, although militarily speaking, one of them was not a commissioned officer.
Feldwebel (roughly equivalent to a United States Army Staff Sergeant) Kurt Knispel served in the 503rd Heavy Panzer Battalion, where he was credited with the destruction of 168 enemy tanks, primarily while operating a Tiger I. Knispel is considered to be the leading tank ace of the Second World War by the German Army, and the most successful tank commander of all time. He spent most of the war fighting the Soviets, and died in action in April 1945.
Oberleutnant (First Lieutenant) Otto Carius served in the 502nd Heavy Panzer Battalion, also on the Eastern Front, where he was credited with more than 150 enemy tanks destroyed. He later commanded a tank company. Although most of his fighting was on the Eastern Front he survived the war and surrendered to the United States Army in May of 1945. He lived in Germany until 2015 operating a drug store named (in German) Tiger Pharmacy.
Hauptman (Captain) Johannes Bolter also served in the 502nd Heavy Panzer Battalion, usually in a Tiger I tank, from which he destroyed 139 enemy tanks, and possibly as many as 144. Martin Schroif is usually credited with more tank kills than Wittmann as well.
Wittmann served on the Eastern Front (with occasional postings elsewhere) until just before the Allied invasion of Normandy after which he operated against primarily British units, and later Canadian units of the British Army. His success against these troops, at a time when the German Eastern Front was beginning to crumble before the Soviet onslaught in 1944, was widely exploited as a morale builder by the German propaganda machine, greatly enhancing his reputation during the war.