Jörg Johnen opened his first gallery in Cologne in 1984, with an exhibition of works by Thomas Schütte and Aldo Rossi. The gallery organized more than 250 exhibitions, first as Johnen+Schöttle in Cologne, and since 2004 as Johnen Galerie in Berlin.
Renowned artists such as Stephan Balkenhol, Candice Breitz, David Claerbout, Martin Creed, Katharina Fritsch, Rodney Graham, Andreas Gursky, Candida Höfer, Martin Honert, Yoshitomo Nara, Thomas Ruff, Anri Sala, Thomas Schütte, Tino Sehgal, Wiebke Siem, Jeff Wall, Liu Ye and many others presented some of their earliest works with the gallery.
In connection with the gallery's 30th anniversary, Johnen opened an additional exhibition space in a landmarked 1825 buidling situated in the courtyard of the gallery with works by Martin Creed.
The Johnen Galerie merged in 2015 with Esther Schipper, who after a two-year transitional period has assumed all operations.
In 2018 his book "Marmor für Alle. Zur Kunst im öffentlichen Raum in Berlin" was published by Mitte/Rand Verlag.