The growth of white-collar unionism and its impact on British trade unions in the postwar period has received little attention from social historians. Radical critics have noted the failure of Clive Jenkins to provide a clear lead in defending workers' conditions, while mainstream, institutionalist commentators more often stress the diversity of specific interests served by such unions. Recent research has called into question earlier models of union governance, though there remain few studies of the history of officer relations within trade unions. This article examines the leadership of ASTMS in the decade after its formation. It is argued that the strategies pursued by Jenkins, including the recruitment, training, and deployment of fieldworkers, were guided by accumulated knowledge and culture (as well as brilliant opportunism) rather than by the structure of the union or the composition of the membership. In offering educated officers a career structure, ASTMS increased its capacity for expertise and effective communication without descending into the political sectarianism of the postwar years. The charismatic, capricious style adopted by Jenkins, as well as the difficulties of absorbing a diverse membership in this period of rapid growth, contributed to the tensions which culminated in a series of struggles between the union and its bargainers during the 1970s.