He saved more Jews from death in the Holocaust than any other Jew. His reward was the accusation that he sold his soul to the devil and assassination by Jewish extremists.
But Kastner's reputation may be about to be restored, more than 60 years after he negotiated a "blood for money" deal with an armed, drunk and often ranting Adolf Eichmann to save Jewish lives in exchange for cash, jewels and trucks.
Two new books about Kastner have been published and a documentary film is being prepared for distribution later this year. All paint him as a hidden hero of the Holocaust, a man who risked his life in countless bargaining sessions with the Nazis.
During World War Two, he negotiated a train to carry almost 1,700 Hungarian Jews to safety in Switzerland, while he stayed behind to continue negotiating.
Later in the war, he also accompanied an SS officer on visits to concentration camps to tell commandants to stop the killings, saving up to 100,000 Jews according to some experts.
At that point, it was clear that Germany was on the verge of losing the war and there would be trials afterward. SS Col. Kurt Becher took Kastner along possibly because he wanted a Jewish witness to his good deed.
Anna Porter, whose book "Kastner's Train" draws on seven years of research, scores of interviews and previously unknown papers, says that it is time to honor Kasztner and to dismiss the many accusations against him.
The second book, German literature professor Ladislaus Lob's "Dealing with Satan: Rezso Kastner's Daring Rescue Mission," is part reexamination of Kastner and part memoir.
Lob was 11 years old when he escaped with his father on Kasztner's train to Switzerland from the Bergen-Belsen camp.
At the time, Kastner was an obscure official of a minor Zionist committee but who had links with Jewish rescue groups in the United States, Turkey and Switzerland.
"He was a nobody who had muscled his way into the negotiations," said filmmaker Gaylen Ross. "He was just a member of a small group of Zionists." Ross' upcoming film has the working title of "The Persecution and Assassination of Dr. Israel Kastner."
After the war, Kastner and his family emigrated to Israel.
Complaints against him surfaced along with a scathing book by American screenwriter and journalist Ben Hecht. Hecht painted Kastner as a Nazi collaborator who withheld key information from the Allies, stuffed the train with his own relatives and charged for the seats.
Kastner had saved 19 of his relatives by getting them seats on the train but 100 other relatives died in Auschwitz.
As for making money off the train, 150 people paid for tickets and that was enough to cover the costs of the other, poorer Jews.
In 1952 he was accused of collaborating with the Nazis by Machiel Grunwald, an elderly pamphleteer.
The Israeli government sued Grunwald for libel but the trial proved to be an all-out attack on Kastner, with the lone judge ruling that he had made a deal with the devil.
The verdict was overturned in 1957 but by then it was too late. Kastner had been assassinated outside his home by three extremists, his reputation already dead in the courtroom.
Holocaust author and Nobel Peace Prize winner Elie Wiesel says of Kastner, "I followed his trial and I think he wanted to help but he chose the wrong method."
Ross, the filmmaker, likened Kastner to the Rorschach inkblot test, a psychological evaluation in which patients are asked to interpret inkblot patterns.
"For me, Kastner is a Rorschach test. People put on him what they feel," Ross said.
First and foremost, there is the guilt felt by the survivors for having lived while others died and then there are the moral questions of dealing with the Nazis and of buying Jewish lives for cash, Ross said.
Jews questioned the motives of other Jews, forgetting that the Holocaust was a crime against humanity perpetrated by the Nazis, not Jews, Ross said.
For Porter, the Kastner story is how his acts of bravery could be so fiercely debated even though they equaled those of righteous Gentiles Oskar Schindler and Raoul Wallenberg.
"He wanted to be seen as a savior of Jews and he was essentially a good man. Schindler called him the most fearless person he knew," Porter said.