Abstract The organization of workers into craft unions in the United States during the Gilded Age (1865–1900) can be interpreted as a search for viable strategy. The American Federation of Labor (AFL) successfully built a durable movement - based on the emergence, development, and consolidation of a distinctive ‘logic of particularism’. Workers’ strategic behavior was based on building and sustaining organizations able to survive periods of economic difficulty and political repression. The analysis shows that organized labor increasingly relied on exclusionary principles in which inclusion within the organized segment of the working class involved a repeated scaling down to a defensible core. This process also reflected the impact of macro-historical structural forces. The combination of strategic behavior and structural influences causally explains the establishment of a narrowly-based and emphatically particularistic working class movement.