Markus Prachensky was born in Innsbruck on 21 March 1932. After finishing school with examinations that qualified for university entrance, Markus Prachensky moved to Vienna in 1952, where he began to study architecture under Lois Welzenbacher at the Art Academy. In parallel Prachensky studied painting from 1953. Together with Wolfgang Hollegha, Josef Mikl and Arnulf Rainer, Prachensky was a co-founder of the 'Galerie nächst St. Stephan' in 1956, whose principal patron was Monsignore Otto Mauer, a well-known art historian. By 1957 the group was introduced to the public at a large-scale Viennese Secession exhibition and Prachensky became a member of the Secession. While staying in Paris in 1958, Markus Prachensky met contemporaries such as Jean Arp, Pierre Soulages, Yves Klein and Sam Francis. The first performance of 'Peinture liquide' was put on at the Theater am Fleischmarkt in Vienna in 1959 and Markus Prachensky participated in documenta II in Kassel. Early in the 1960s Prachensky spent quite some time in Berlin and Stuttgart, where he did the sequence 'Rot und Rot - Berlin' in 1964-66 as well as the Solitude pictures. Whereas Markus Prachensky's early work still follows stringently geometric composition, from the 1960s Prachensky developed an inimitable tachist handling with leanings towards international Informel. In 1967 Markus Prachensky went to New York, where he met Clement Greenberg. A year later Markus Prachensky moved to the US and set up a studio in Los Angeles but he also stayed at Palm Springs and travelled to Mexico. Returning to Europe in 1969, Prachensky worked at first in Hanover but from 1971 he again worked and exhibited in Vienna. In 1972 Markus Prachensky was commissioned to execute an enormous tapestry for the Congress House in Innsbruck. Since 1975 Prachensky has travelled extensively over long periods in the Mediterranean, visiting Italian archaeological sites, which he has found a source of inspiration. Until the mid-1970s Prachensky's painting concentrated on reds but impressions gleaned in Italy enlarged his palette to include black and yellows. Mediterranean landscapes, the colours and forms of Italy, were at the core of the sequences Markus Prachensky painted during the 1980s and 1990s. From 1983 until 2000 Prachensky taught and directed the master classes for painting at the Viennese Academy of Art. In 1992 Markus Prachensky was awarded the Medal of Honour in Gold of the City of Vienna and in 2003 he received the Prize of the City of Vienna for the Visual Arts. Large-scale retrospectives of Markus Prachensky's work were mounted at the Hannover Kunstverein in 1970, at the Viennese Academy of Art in 1979, and, on the occasion of Prachensky's seventieth birthday in 2002, at the Österreichische Galerie im Oberen Belvedere. In 2003 Pachensky's work was displayed at the Galerie Ulysses in Vienna and in the Essl Collection, Klosterneuburg. Markus Prachensky is one of the most important exponents of Informel in Austria.
The artist dies in 2011 in Vienna.