Renner was born as the 18th child of a poor farmer's family but because of his talents he was allowed to go to high school and study law at university. Renner has always been interested in politics and became librarian in parliament and member of the Austrian social democrats party (SPÖ) in 1896. He started to represent the party in the Imperial Diet in 1907. Afterwards, Renner was Chancellor of Austria and Minister of Foreign Affairs from 1918 until 1920.
The peace treaty in St. Germain was as well under the leadership of Karl Renner and from 1931 to 1933 he was President of the Representative Assembly. He always plead for the annexation of Austria with Germany but distanced himself from politics during the wartime. After the collapse of the Third Reich, Renner tried to build up a Provisional Government and stood up for Austria to be acknowledged as an independent republic. He was the first Chancellor after World War II. In 1945 he became the first president of the Second Republic.
On his passing in 1950, Karl Renner was buried in the Zentralfriedhof in Vienna.