Although much has been written on the German jurist Carl Schmitt's commentary on liberal democracy and parliamentarism, his analysis of monarchy and monarchism has remained overlooked. This article excavates Schmitt's analysis of monarchy and the monarchical principle articulated during the Weimar Republic. Although Schmitt never devoted a text to exploring monarchy as he did for other state forms, this article argues that the monarchical principle is nevertheless central to his account of political representation presented in his Constitutional Theory and can only be properly understood when contextualized in his shorter, contemporaneous writings. The article then explores the relationship between the monarchical principle and Schmitt's understanding of constituent power in the figure of the republicanized monarch.