Abstract: Despite the historical turn in the study of public international law and the advance of comparative approaches, still too little attention is paid nowadays to specific national traditions. This holds, inter alia, for the scholarly views and practices in the Netherlands during the first half of the 20th century. This article seeks to shed light on the experiences here at the advent of the League of Nations and its tentative 'new world order'. Offering a meso-level analysis, it portrays the leading protagonists during the 1920s and 1930s, aiming to provide a snapshot of how their discipline and activities underwent an unexpectedly swift professionalization. This process is perceived to have run along three distinct vectors - academic, societal and diplomatic/bureaucratic - which are each examined in turn. Novel opportunities stemming from the rise of the international judiciary, especially the two Permanent Courts established on Dutch soil, are looked at separately. The research delivers a greater insight into the interwar era and the challenges faced by (academics from) smaller nations, enabling us to situate underexplored local experiences within a global frame, and offering useful lessons for (the writing of) international law history more generally.