Surrealism, cubism, genre painting of the nineteenth century, historical paintings, gestural painting of the 1950s, contemporary pop art, and obviously the works of his contemporaries – Penck had many inspirations, but he transferred them into a completely autonomous language of images and forms: clear lines, pictogram-like forms, stick figures on canvases that sometimes assume enormous sizes. Current events, universal themes, as well as personal experiences are all present in his concise and unprecedented world of images. In 1980, due to increasing political pressure, Penck emigrated to West Germany, where he met and became friends with Joseph Beuys, Jörg Immendorff, Markus Lüpertz, and Per Kirkeby.

He was one of the most important painters advancing the renewal of painting in Germany, yet he stayed true to his own aesthetics that he had developed back in Dresden. In East Germany, he remained mostly unknown, his smaller exhibitions there having little success. His art, fluctuating from abstraction to figuration, did not fit into the aesthetic ideals of socialist realism. However, in West Germany his paintings were celebrated. In 1971, Haus Lange in Krefeld was the first museum to house his solo exhibition. In 1972, Penck took part in documenta for the first time and, together with Joseph Beuys, had his works displayed in the State Gallery of Modern Art of the Bavarian State Painting Collections in Munich. His paintings and bronze sculptures, which he created from 1982 onwards, have been displayed in galleries and museums around the world. Penck moved to London in 1983, and then to Dublin in 2003. From 1988 to 2003, he was a professor at Kunstakademie Düsseldorf.