She was born on 23rd February 1928, in the village of Srebrniki, in the district of Kowalewo Pomorskie, located in the Province of Kujawsko-Pomorskie. She was a theatre and film actress.
Her acting début came in 1949, on stage of the Wilam Horzyca Theatre. Much later, in 1954, she passed an external exam at an acting school. She was continuously involved in the Polish theatre scene up until the 1980s, which marked the moment when she decided to abandon her professional acting career. After the Toruń period, she went on to perform at the Wojciech Bogusławski Theatre in Kalisz (in the years 1951-52), the Polish Theatre in Poznań (in the years 1952-54), the Stefan Jaracz Theatre in Łódź (in the years 1960-66), the Polish Theatre in Warsaw (during the 1967-68 season), and then again at the New Theatre in Łódź (in the years 1967-1983).
Urszula Modrzyńska played in over 20 films. In 1954, she played Dorota in the film Pokolenie / A Generation directed by Andrzej Wajda. In 1957, she was cast to play the main character in the film Deszczowy lipiec / Rainy July directed by Leonard Buczkowski. In 1960, she played in the super-production Krzyżacy/Knights of the Teutonic Order directed by Aleksander Ford, where she impersonated Jagienka. That was the acting creation she is most remembered for.
The actress was also cast for television films dedicated to the young audience, for example in Wielka, większa i największa (1962) directed by Anna Sokołowska, in a TV adaptation of the novel Niewiarygodne przygody marka Piegusa (1966) written by Edmund Niziurski, which was directed by Mieczysław Waśkowski, or in the TV series Siedem stron świata (1974) directed by Wojciech Fiwek and Tadeusz Junak. In the film Zdjęcia próbne / The Film Test (1976) directed by Agnieszka Holland, Paweł Kędzierski and Jerzy Domaracki, she played the mother of the main protagonist.
Urszula Modrzyńska also performed in radio dramas and TV theatre plays, for example in the drama Warszawianka (1960) written by Stanisław Wyspiański, adapted and directed by Kazimierz Dejmek.
In 1980s, she withdrew from acting completely, which was caused by a serious illness. She died on 11th December 2010, in Łódź.