Semjan studied fine arts from 2001 to 2006 as a master student of Joseph Kosuth, at the Academy of Fine Arts in Munich. As of 2011 he lived and worked in Brussels, Belgium and Munich, Germany. Throughout his career, he worked in different media to express his mostly political concepts. In an exhibition at the Baumwollspinnerei in Leipzig, Germany, in 2008, he showed different screenprints on steel, which were exposed to the elements for several months and therefore corroded to develop a new picture language. The paper and cardboard model of the Oval Office "Park View Office to Let“ (2007) is a reproduction of 16 square metres (170 sq ft), which was exhibited at Art Brussels 2007 in a Solo show by Gallery Traversée. Jens Semjan received grants from the Cultural Foundation of Allianz, Erwin and Gisela von Steiner-Foundation and the Karin Abt-Straubinger Foundation. His works are held in different collections including the Allianz SE and Alpine Bau Deutschland AG.
Semjan advocated a critical review of the relative priority of educational institutions versus theaters and art museums: "museums and theaters should be provided with the opportunity to sustain an economic activity.“The Grand Insolvency Show is a polemic exhibition which focuses on a visionary and liberal idea of visual arts – Statistics. It projects 320 slides with confronting statistics, across a range of global themes via four Kodak carousel projectors. The exhibition was edited using publicly available data from global sources, but with the concept of turning serious statistical analysis into engaging art: The curves, columns and pie charts themselves are readymade pictures.