Jakub Frostig (1896–1959) was one of the most active Polish psychiatrists of the interwar period, with broad scientific interests, maintaining close scientific contacts with the leading specialists of world psychiatry, from the German –and English-language areas. This aspect of his activity is presented in the two-part publication based on new sources, which have never been used before, especially on the correspondence with Ludwig Binswanger (1881–1966), Max Müller (1894–1980) and Adolf Meyer (1866–1955), spanning several years. In addition, the German-language work of the psychiatrist and its reception in this language area are described in more detail for the first time. The first part of the article discusses the little known participation of Frostig in the Polish psychoanalytic movement and his attempts to popularize psychoanalysis in Lviv in the 1920s, as well as the philosophical inspirations of his work from the early period of his scientific activity. Frostig’s ambitions and chances for a scientific career did not always go hand in hand. The work presents the causes of these discrepancies, which limited his career in the period before and after his emigration to the United States in 1938.