Tarski served as a professor at the university in his native city of Warsaw (1925–39). In 1942 he joined the staff at the University of California and became professor there in 1949 and research professor at the Miller Institute (1959–60).

Tarski worked on set theory and algebra and is noted as one of the pioneers in the study of formalized logical systems as purely algebraic structures. He emphasized the difference between the metalanguage, used to talk about these structures, and the formal language whose syntax formed the system being studied. His famous paper The Concept of Truth in Formalized Languages (1935) was one of the foundation stones of model theory and has had a profound influence both in logic and the philosophy of language.