This article studies transnational biography avant la lettre by looking closely at Klaus Mann's 1943 portrait of the French writer André Gide. Writing against the backdrop of the battle against Nazism and war, Mann presents Gide as an exemplary European, who combined a strong national identity with an open, cosmopolitan mindset. The article shows how he unpacks his subject's multiple identities, while presenting a coherent life narrative, structured around the polarities of individual/communal and national/European. It further examines how writing Gide's biography influenced Mann's self-presentation as a European artist in his autobiography The Turning Point, thus aiming to reach a better understanding of how transnationalism is lived and produced through life-writing practices. Finally, this article explores the pitfalls and challenges of transnational biography by looking closely at Mann's use of national categories and his tendency to associate transnationalism with idealizing notions of crossing and breaking down borders.