In 1917 he published an open letter to Kaiser Wilhelm II in the newspaper Neue Zürcher Zeitung calling for his abdication, and was charged with treason and lèse-majesté as a result.
Serge writes as an architectural critic for the Neue Zürcher Zeitung and has a teaching experience from the Watermill Center on Long Island and the University of Barcelona.
In addition to his scouting engagement, Karlsen have been working freelance for TV 2 (Norway), BBC Radio, FIFA Magazine, SportBild, Neue Zürcher Zeitung, The Independent, The Times and Four Four Two as an football expert and analyzer.
Frankfurter Allgemeine Zeitung | Süddeutsche Zeitung | Neue Zürcher Zeitung | Neue Pinakothek | Vossische Zeitung | Neue Slowenische Kunst | Berliner Zeitung | Berliner Illustrirte Zeitung | Arbeiter-Illustrierte-Zeitung | Neue Nationalgalerie | Hallen für Neue Kunst | Frankfurter Zeitung | Arbeiter-Zeitung | New Yorker Staats-Zeitung | Neue Südtiroler Tageszeitung | Neue Freie Presse | Arbeiter-Zeitung (Vienna) | Zürcher Theater Spektakel | Zürcher Oberland | Westdeutsche Allgemeine Zeitung | ''The Siege of Cosel'', 1808, Oil on canvas, 202 x 305 cm, Neue Pinakothek | Neue Volkszeitung | Neue Rheinische Zeitung | Neue Rechte | Neue Liebeslieder | Neue Künstlervereinigung München | Neue Gesellschaft/Frankfurter Hefte | Neue Galerie New York | Neue Deutsche Welle | Neue Deutsche Biographie |
His articles have been published by all major newspapers and magazines in Britain, Germany, Switzerland, Australia and New Zealand, including The Sunday Telegraph, Die Welt, The Australian, The Sydney Morning Herald, Neue Zürcher Zeitung, and The Dominion Post.
He also writes for German newspapers and magazines like Die Zeit, the Neue Zürcher Zeitung, Die Welt, Frankfurter Rundschau, the Neue Rundschau and the Merkur.
From 1974 to 1997 he worked for the Swiss Neue Zürcher Zeitung and the Australian Cinema Papers as a correspondent from Los Angeles, responsible for reporting about the film industry.