Jähner studied literature, history and art history in
Freiburg and completed his doctorate in
Berlin. After graduation, he worked as a freelance journalist. Jähner was head of the communication department of the House of World Cultures in Berlin. At the same time from 1994 to 1997 he wrote as a freelance literary critic for the
Frankfurter Allgemeine Zeitung. He then worked as an editor at the
Berliner Zeitung, where he headed the
Feuilleton department from 2003 to 2015. Since 2011, Jähner has been honorary professor of cultural journalism at
Berlin University of the Arts. In 2019, Jähner published
Wolfszeit, a consideration of German life in the post-war decade 1945–1955, published by Rowohlt Berlin. == Awards==