She was the daughter of royal counselor and marschal count Erik Sparre af Sundby and Stina Lillie. She married Count Carl Gustaf Tessin on 27 August 1727. She accompanied her spouse on his diplomatic assignments to Vienna (1735–36), Copenhagen and Paris (1739–41) and Berlin (1744). She is described as a talented artist and a skillful socialite, was admired for her character, and skillfully created valuable social contacts during the diplomatic stays abroad.
In the 1730s, the couple participated in the amateur theatres in Stockholm which played an important part in creating an interest for the foundation of the first Swedish language national theatre in Bollhuset (1737); in 1732, Dom Japhlet d'Arménie by Scarron was performed by a noble amateur theatre at Bollhuset, directed by the Tessin couple, who also participated as actors.
Ulla Tessin was a confidante of the crown princess, Louisa Ulrika of Prussia, and when Louisa Ulrika became queen in 1751, Tessin was appointed her head lady-in-waiting. At the fall and dismissal of her spouse in 1754, she resigned and initially managed to do so without falling out of favour with the queen; eventually, however, the queen broke with her as well and the couple retired to Åkerö manor.
Ulla Tessin was a Dame of the L’Ordre de l’Harmonie.
- Tessin, 4. Ulrika (Ulla) Lovisa i Nordisk familjebok (andra upplagan, 1919)
- Tryggve Byström: Svenska komedien 1737-1754 (1981)