From 1941 to 1945 he was an inmate of various concentration camps, including Buchenwald and Mauthausen, from which he was liberated by the United States Army. Since then he has devoted himself intensely to the hunt after Nazi criminals. He joined the American Commission for War Crimes and was later transferred to the O.S.S. at Linz. In 1946, with 30 survivors of the concentration camps he established the Jewish Historical Documentation Center in the American Zone, which was closed from 1954 to 1961, and reopened in the latter year in Vienna. He concentrated on the identification of Nazi criminals and was instrumental in forwarding the data which led to the capture of Adolf Eichmann. He brought over 1,100 Nazi criminals to prosecution.

Wiesenthal was the recipient of numerous awards, among them the title Commander of the Order of Orange by Queen Juliana of Holland in April 1979, the highest civilian award of The Netherlands and Commendatore de la Republica Italiana by President Pertini in October, 1979; in August 1980 he was the recipient of a special gold medal for humanitarian work from the Congress and the Senate of the U.S.A. presented to him at the White House by President Carter who praised him for “keeping the flame of justice alive in the world.” In December 1980 he was presented with the Jerusalem Gold Medal by Teddy Kollek, mayor of Jerusalem. Among the many books published by him are The Murderers Among Us (1967) which has been translated into 21 languages; The Sunflower (1969) on the problem of forgiveness; and Sails of Hope (1973) both of which have been translated into 14 languages.