Prinzhorn was educated in engineering at the Technical University of Vienna, where he graduated in 1967 as Diplomingenieur, and subsequently studied business administration at Harvard University, graduating in 1973.
Prinzhorn inherited his father's business empire and became one of Austria's leading industrialists in the 1970s. He served on the board of the Federation of Austrian Industry from 1978 . With a personal fortune of around 1.1 billion euro, he's considered Austria's richest politician and the 14th richest Austrian (as of 2006) Thomas Prinzhorn studied mechanical engineering at the Technical University in Vienna and graduated in 1967 with the engineer from. In Harvard Prinzhorn studied also economic, concluding there he made in 1973. As a result, he established himself with the company of his father, W. Hamburger AG and the AG Mosburger than paper industrialist.
As a longtime CEO in various companies in the paper industry, he came across the Federation of Austrian Industry in politics. He became 1978 member of the Board of the Association of Austrian Industry, 1975-1988, he was chairman of the Committee on Education and Social Policy, 1988-1993 Chairman of the Economic Policy Committee and from 1991 to 1993 president of the Vienna Industrialists. In 1996 he was first elected to the National Council, which he belonged until 1998. At that time he said goodbye after nearly three years in the National Council of all functions. The reason back then: Massive differences of opinion with respect to the Haider-course . Here Prinzhorn had then helped decisively, for the account of the Causa Rosenstingl create a restructuring plan has come into considerable financial difficulties FPÖ Lower Austria. Member of the FPÖ was Prinzhorn only 1998th
For the National Council election in 1999, He was originally expecting a nomination for a ministerial post provided he was in the course of forming a government in 2000 by Federal President Thomas Klestil for perceived as particularly tasteless xenophobic statements during the election campaign rejected. Instead, he was nominated by the Freedom Party, which was the second largest at that time party to the Second National Council President, giving him a few days, however to come up with a campaign. In autumn 2002, it looked as if he should again play a greater role in the party, because in September 2002 he was diagnosed in Linz as the deputy party leader. After the early parliamentary elections in 2002, however, the FPÖ fell back to third place, in the result was Prinzhorn from now third National President. The entrepreneur and economic spokesman for the Freedom Party was at that time mainly as a support of the government team led by the former Vice-Chancellor and FPÖ chief Susanne Riess-Passer . The relationship with Carinthia's Governor Jörg Haider was against noticeably cooled in the meantime. As part of the intra-party turmoil and its related materiel withdrawal from the FPÖ in 2005, he was still to April 27, 2006 Member of the services of the FPÖ, thereafter for up to 29 October 2006, the BZÖ. The Office of the Third Speaker of Parliament he had held until 30 October.
A former member of parliament, Prinzhorn served as one of the three presidents of the Austrian Parliament from 1999 to 2006. In 1996, he was elected to parliament; becoming a member of the Freedom Party of Austria (FPÖ) in 1998. In the 1999 legislative election, he was the top candidate of the FPÖ. He was originally slated to be part of the FPÖ-ÖVP coalition government, but his candidacy was rejected by President Thomas Klestil (due to his anti-immigration statements during the election). He was instead elected one of the three presidents (second president) of the Austrian Parliament. After the 2002 election, he became third president. He left the FPÖ in 2005, and joined the new BZÖ party in 2006.
Prinzhorn adopted Karl Philipp Ernst Ferdinand Alwig Kilian Schwarzenberg (b. 1979), until then legally the son of Karel Schwarzenberg (the former Czech Foreign Minister). On 20 March 1990, Karl Philipp began using the surname "Prinzhorn".