One of the prisoners, Stanislaw Szmajzner, described him in his memoirs as follows:

We never learned his name (…) we immediately gave him the nickname ‘Trottel’ meaning idiot. We did this because that’s what he called us. “Trottel”, an obese man, almost as round as he was fat, still walked very nimbly and confidently. Very red in the face, he loved to show his authority by not talking much, even to his officers. He always shouted at us and liked to give us constant orders that had to be obeyed to the very last dot.

He was born in Ried, Austria. He joined the NSDAP and SS even before Austria joined the Third Reich. When the Anschluss occurred, Reichleitner served in the Gestapo in Linz. In his home country, he joined Operation T4, in which he worked as a staff member in the “euthanasia center” at Hartheim Castle. During his service there, he met many of the future Sobibor camp staff.

In 1942, Commander Stangl was transferred from Sobibor to Treblinka, and Reichleitner was designated as his replacement. One of the first decisions he made was to expand the gas chambers, regarding which he personally created instructions on what the work should look like. The new commandant also ordered the exhumation with an excavator of the bodies of those previously murdered and their burning. During his rule, some 100,000 people died in the camp. He himself supervised some of the executions. One of them was the shooting of a dozen people in retaliation for the escape of a group of prisoners working in the camp forest. A surviving Sobibor prisoner, Moshe Bahir, recalled:

One time, when an elderly man from the transports beat up an SS officer, Commander Reichleitner took him aside and shot him on the spot, in front of his family and the entire convoy of people.

However, the new camp commander rarely visited the camp. Compared to other commanders, Franz Reichleitner also seldom personally supervised the receiving of transports or the directing of victims to the gas chambers. When the Sobibor uprising broke out, he was not present at the camp because he was on leave. Later, he oversaw the liquidation of the camp and the obliteration of the traces of the crimes committed there. Like many other members of Operation Reinhardt, he was transferred to the Balkans, in occupied Yugoslavia. The unit in which he served was responsible for liquidating local Jews and fighting Italian and Yugoslav partisans.

Franz Reichleitner was killed in Fiume (now Rijeka) in a skirmish with partisans. He was buried in a German cemetery in Italy.