He graduated from High School in Horn in 1935 with distinction and started to study law at the University of Vienna. Subsequently he passed the exams and graduated to Doctor iuris.
Born in Niederkappel, Upper Austria, Kirschläger was orphaned at the age of 11. However, after the Anschluss of Austria in 1938, he had to give up his studies. Without joining the NSDAP, which he refused to do, his scholarship was revoked and Kirchschläger could not finance his studies any longer.
Kirchschläger worked as a bank clerk in 1938 until he was drafted to service in the infantry of the Wehrmacht in the summer of 1939.
Kirchschläger fought as a soldier from the very beginning of the war, first during the invasion of Poland, later on the Western Front, and after 1941 against Russia on the Eastern Front. In late 1940, in order to get out of the military, he used a two-month front-leave to prepare for the final exam (Staatsexamen) of his law studies.
Legend has it that he was working up to 20 hours a day, while keeping himself awake with large amounts of honey. However, he was sent back to the Eastern Front, where he was wounded in 1942.
Towards the end of war, he was captain and training officer at the military academy at Wiener Neustadt in the Vienna region.
In early April 1945, commanding a company of cadets fighting approaching Soviet troops, he was badly wounded on his leg, an injury from which he would never fully recover. After the war Kirchschläger worked as a district judge until 1954 in Langenlois and later Vienna. In 1954 he got the chance to work in the Ministry of Foreign Affairs, although he did not speak any foreign languages.
In order to take part in the negotiations on the Austrian State Treaty he taught himself English in only a few months.
From 1967 to 1970 he was ambassador in Prague. Despite orders not to do so he issued exit visas to Czechoslovakian citizens who tried to flee from the Communists during the Soviet invasion of Czechoslovakia.
From 1970 to 1974 he was Minister of Foreign Affairs and was elected President of Austria in 1974. In a programmatic lecture at Innsbruck University in February 1971 he outlined his understanding of an "ethical foreign policy".
His integrity as President and his diligence in exercising his office raised him to be an admired and beloved figure within Austrian politics.
In 1974, he pardoned the convicted Austrian Nazi war criminal Franz Novak, who had coordinated the railroad deportation of European Jews to concentration and extermination camps. In 1980 he was elected for a second term with an approval rate of 80%, the highest rate ever obtained in any presidential elections. In February 1984, Kirchschläger paid the first state visit of an Austrian President to the United States.
Rudolf Kirchschläger died in 2000 near Vienna, aged 85, of undisclosed causes.
Of Austrian delegation to United Nations General Assembly.
Married Herma Sorger in 1940.