He attended school in Bregenz before from 1950 he studied law at the University of Innsbruck, where he graduated with a doctorate in 1954.

[4] Kieber was the Prime Minister of Liechtenstein, serving from 27 March 1974 to 26 April 1978.

[4] The 1974 Liechtenstein general election resulted in a win for the Progressive Citizens' Party and Kieber was appointed prime minister.

[5] In 1975, he was a signatory of the Helsinki Accords to create the Conference for Security and Co-operation in Europe, the precursor of today's OSCE.

[1] The Progressive Citizens' Party lost the 1978 Liechtenstein general election and Kieber again served as deputy prime minister from 26 April 1978 under Hans Brunhart.