[1] Kateryna Rubchakova was born on 29 April 1881 in Chortkiv to a deacon and amateur conductor of the city choir, Andrii Kossak (1850–1917), the son of a blacksmith and weaver Ivan Kossak from the village of Bila near Chortkiv, and his wife Rozaliia Hryhorivna Fedorovych (1856–1923), the daughter of peasants from Vyhnanka.

[6][3] She performed on stage with Amvrosii Buchma, Maria Zankovetska, Marian Krushelnytskyi, Les Kurbas, Antonina Osypovych, Mykola Sadovskyi, Vasyl and Hanna Yurchak, and others.

[2][3] In 1958, thanks to the efforts of her daughter Olha, she was reburied at the Mykulynetskyi cemetery next to the grave of actress Teodoziia Bentsaleva.

[3][7] She has played 79 dramatic, 27 operetta, and 18 opera roles,[5] among others:[2] The best opera roles:[2] The theatre director Stepan Charnetskyi wrote about her performance as Ryta in Vynnychenko's drama: "Rubchakova came to the fore among the performers, who, playing the Black Panther, was especially famous in Act II...".

[2][6] In Chortkiv, a house of culture was named in Rubchakova's honor and a bust was erected (1991, sculpted by Dmytro Stetsko).