[1] He is most known in Austria for helping to expose the child sex abuse scandal of Archbishop of Vienna Groer as well as the Nazi past of former United Nations Secretary-General and Austrian President Kurt Waldheim, and is most known in the United States for being instrumental in the eventual restitution of Gustav Klimt's Adele Bloch-Bauer I - as depicted in the movie Woman in Gold - to its rightful Jewish heirs.
Soon after he published a series of articles about the "suspicious" ownership of five famous paintings from artist Gustav Klimt, proving that claims by Austria that they had been donated to the gallery by Adele Bloch-Bauer were misleading.
Adele had, in fact, requested in her will that the paintings be donated to the Österreichische Galerie Belvedere in Vienna upon her death, but in his plumbing of the archives, Czernin discovered the will of her husband Ferdinand Bloch-Bauer, who died 20 years after Adele and was the person who paid for the paintings.
In 2004 a United States Supreme Court ruling allowed Altmann to sue the Austrian government for ownership of the multimillion dollar Klimt paintings in the United States, and in 2006 Altmann successfully restituted the paintings.
[6] In 2006, just weeks before his death, Czernin was able to see the Klimt paintings debut for the first time on American soil at an exhibition at LACMA.