She was a formative figure in Berlin's lesbian subculture from the time of the Weimar Republic to the early 1980s as an organizer of clubs, balls, and meetings, and as a bar operator.
In the 1920s she ran the largest clubs for the lesbian movement, which served up to 2,000 people, and worked, among others, with Charlotte “Lotte” Hahm.
The club founded in 1928 by the women's group of the German Friendship Association, one of the largest homosexual organizations in the Weimar Republic.
Despite its relative youth, the Monbijou club already enjoys a large following in the better circles of young girls [ ...] The highlight of these evenings is the wonderful play of lights, which is worth seeing - soon the large, beautiful hall is ablaze with purple, then green again, or it suddenly turns into a deep, rich red, in whose soft light the couples follow the sounds of the music.
Two days earlier, the announcement came that Kati Reinhardt and the club were leaving the German Friendship Association, merging with the Violetta club under Lotte Hahm, which also belonged to the DFV, and joining together to form the DFV's larger competitor organization, the Bund für Menschrecht under Friedrich Radszuweit.
[3] In addition to her organizational role, Reinhardt appeared regularly as a singer, and contemporary reports highlighted the quality of her singing.
[8] Unlike prominent representatives of the first lesbian movement such as Hahm or Engler, Reinhardt appeared neither as an author nor as an activist, but instead limited herself entirely to her work as an organizer.
Reinhardt was extraordinarily popular; in 1931, the magazine The Girlfriend wrote that "as a magnificent person and artist, she knew how to win the hearts of all members".
[citation needed] A few months after the end of the war, Reinhardt and her partner, Eva Kohlrusch, moved into a small apartment on Kulmbacher Strasse in Schöneberg.
Reinhardt promoted this through small advertisements in Aphrodite, a supplement for lesbian women published from 1956 to 1958 in the homophile magazine Der Ring.
[2] The young Gisela Necker frequented there from 1959 and remembered it in 2011: “Back then there was a club called 'Bei Kathi' in a backyard on Augsburger Straße.
[…] Bei Kathi was still very discreet, with the atmosphere of a club, very plush and with dim lighting; people went there late at night.
The locations changed, around 1950 in the “cabin” behind the Schöneberg town hall, in the winter in the 1950s and in the 1980s in the Hotel Intercontinental,[9] later also in the Eierschale in Dahlem.
[citation needed] With the destruction of their organizations and media by the Nazis from 1933 onwards, the first homosexual movement and its protagonists were increasingly forgotten.
The continued repression in the post-war Federal Republic only led to the first investigations with the lesbian and gay movement from the early 1970s onwards among activists and their interest in their "own history".
[8] In monographic works on the history of the Berlin homosexual movement, Heike Schader in 1994 and Jens Dobler in the early 2000s systematized and supplemented the knowledge about Reinhardt.