After antisemitism at Vienna's Technische Hochschule forced Kallir to abandon his dream of becoming an aeronautical engineer, he decided instead to pursue a longstanding interest in art.

The gallery hosted the first American exhibitions of numerous important Austrian and German modernists in the 1940s and 1950s, including Gustav Klimt, Oskar Kokoschka, Alfred Kubin, Paula Modersohn-Becker, Käthe Kollwitz and Egon Schiele.

[7] The Galerie St. Etienne gained the exclusive representation of Grandma Moses, who became one of the most renowned American artists of the immediate postwar era, in large part thanks to a relationship cultivated by Hildegard Bachert, who joined the gallery's staff in 1940 and later became its codirector.

In a case concerning Oscar Kokoschka's Two Nudes, owned by the Museum of Fine Arts in Boston, the judge ruled against the claimant, Claudia Seger-Thomschitz.

[2]  Similarly, in a case involving a Schiele, Seated Woman with Bent Left Leg (1917), alleged to have been stolen from Fritz Grünbaum (a Holocaust victim),  the judge ruled in favor of the owner, David Bakalar.

Jane Kallir continued the gallery's scholarly tradition, publishing over 20 books on such subjects as Grandma Moses, Gustav Klimt, Egon Schiele, the Wiener Werkstätte and Austrian Expressionism (see Publications for further information).

[2] In addition to writing short texts to accompany each of the Galerie St. Etienne's exhibitions, Jane Kallir became known for her annual "Art Market Reports"[15] While continuing to represent Grandma Moses, starting in the 1980s, the Galerie St. Etienne expanded its roster of self-taught artists to include Henry Darger, John Kane, Ilija Bosilj, Michel Nedjar and the Artists of the Gugging.

The gallery also expanded its representation of Expressionists, with Germans such as Max Beckmann, Otto Dix, George Grosz, Erich Heckel and Ernst Ludwig Kirchner regularly appearing alongside Austrians such as Klimt, Kokoschka, Kubin and Schiele.

A major exception to the gallery's historical orientation was its representation of contemporary British-born artist Sue Coe, whose oeuvre shares close formal and thematic connections with the work of Käthe Kollwitz.

The KRI continues to provide authentications for works attributed to Egon Schiele and Grandma Moses, and cooperates with internationally recognized scholars on pertinent research projects.