From 2013 he was a member of the German Quizzing Association (Deutscher Quiz-Verein [de], founded in 2011) and participated in several national and international competitions.

[4] As a single player or together with a partner, he took part in the annual German Quizzing Championship with varying successes, winning the doubles tournament (with Carsten Happe) in 2014.

[7] He was the organizer of a monthly pub quiz taking place in various bars in the city of Münster and worked on the questions.

[1] As a chaser at Gefragt – Gejagt, the German adaptation of The Chase, Klaus Otto Nagorsnik bore the battle name "Der Bibliothekar“ (English: The Librarian).

In the remaining 34 percent, Nagorsnik's opposing team won an average of €5,456 per appearance, which was rather at the lower end of the profit potential compared to the other chasers.