Jan Uprka was the second eldest son of Joža Uprka, and like his father pursued a creative career, working primarily as a painter, and experimenting with ceramics. In the late 1930s, however, his public life became increasingly defined by an involvement in politics. He became a founding member of the National Fascist Community, and later joined the association Ethnographic Moravia (Národopisná Morava). He emerged as a leading figure among the East Moravian irredentists during the Nazi occupation.

Jan advocated for the annexation of Moravian Slovakia and other parts of eastern Moravia to the Slovak state—an initiative initially considered by Slovak authorities and briefly entertained by Nazi Germany before its ultimate rejection, as it did not fit into German plans for the region.Joža Uprka had long criticized his son's political involvement. After World War II, Jan Uprka withdrew from political life and worked as the administrator of the folk art school in Hroznová Lhota.