In 1978, she became the director of the Galerie nächst St. Stephan in Vienna, which was founded by the Catholic priest de:Otto Mauer, and she became the owner of the gallery in 1987.

In the Galerie nächst St. Stephan, Rosemarie Schwarzwälder initially focused on project-related exhibitions, accompanied by discussions, readings, performances, and concerts (occasionally together with the Wiener Musikgalerie).

[5] From this point forward, Schwarzwälder began presenting the first solo shows in Austria by Imi Knoebel, Helmut Federle, Donald Judd, James Welling, and Dan Flavin.

[6] In 1990, she collaborated with Helmut Federle on a project in which works by contemporary abstract artists were juxtaposed with artifacts from ancient cultures in Asia and South America.

Rosemarie Schwarzwälder has continued to represent the same painters over the years while also expanding the gallery's program since 1992 to include works by younger artists and sculptures and installations.