This paper focuses on Charles Le Maistre, a key figure in spreading voluntary consensus standards-setting from the national to the international realm. He exemplifies Schumpeter's "political entrepreneur"—someone who operated in the realm of partially organized political forces to establish the administrative and regulatory systems that facilitated investment in new generations of technologies and firms. In 1901 he became Assistant Secretary of Britain's new Engineering Standards Committee, an organization that included representatives from professional and industry associations. In 1906 he became acting secretary of the International Electrotechnical Commission, the first ongoing international standards-setting organization. He remained a key player in both organizations for the next fifty years, traveling the world to spread principles of voluntary consensus standard-setting. He helped establish the American national standards organization and the first international standardizing association with a broad domain, the ISA (International Federation of the National Standardizing Associations). During World War II, he worked with the temporary Allied standardizing organization. After the war, he helped dissolve ISA and the war-time association and to form the new ISO (International Organization for Standardization). For half a century he proselytized for standardization, extending it from the national to the international realm.