In 1971, he was appointed the first independent director of the Kunsthalle Kiel[1] and executive chairman of the Schleswig-Holsteinischer Kunstverein. Jensen retired in 1990.[2]
From 1972 to 2005, Jensen was a member of the scientific advisory board of the Museum Georg Schäfer in Schweinfurt. In 1979, he was awarded the Honorary Professorship of the State of Schleswig-Holstein "in recognition of his services to the activation of art life in Schleswig-Holstein and in appreciation of his scholarly achievements in the service of art".[3] Jensen was the author of numerous writings on medieval sculpture, on 19th and 20th century painting and drawing, and on contemporary art. In 2008, he was curator of the exhibition Carl Spitzweg and Wilhelm Busch. Two Artists' Anniversaries in the Wilhelm Busch Museum in Hanover.
Meister Bertram als Bildschnitzer. Das Verhältnis des Doberaner Lettneraltares zu den Skulpturen des Hamburger Petrialtares. Dissertation Heidelberg 1954 (Maschinenschriftlich vervielfältigt 1956).
Jens Christian Jensen (ed.) 100 Jahre Kieler Woche – Lyonel Feininger: Gemälde, Aquarelle und Zeichnungen, Druckgraphik. Verlag: Kunsthalle zu Kiel der Christian-Albrechts-Universität, Kiel 1982
Amerikanische Kunst von 1945 bis heute. Published together with Dieter Honisch. DuMont, Cologe 1976
Christian Rohlfs. Gemälde − Aquarelle. Ausstellungskatalog. Kunsthalle, Kiel 1979
Paul Wunderlich. Eine Werkmonographie with contribution by Max Bense and Philippe Roberts-Jones. Volker Huber, Offenbach 1980
Günter Grass. Hundert Zeichnungen 1955–1987. Ausstellungskatalog der Kunsthalle Kiel. Herausgegeben von Jens Christian Jensen, Kiel 1987, ISBN3-923701-23-3