While the U.S. manufacturing sector has shrunk over the past 30 years, the fully worker-owned Isthmus Engineering & Manufacturing (IEM) cooperative has thrived in the automated manufacturing industry. In a dynamic industry, the firm has grown and constantly adapted to diverse market demands. This case study illustrates the unique organizational structures and dynamic governance mechanisms that are possible in a worker cooperative, and the way that these structures shape decision-making in a demanding market context. In particular, the case shows how the distribution of production-related decision-making in this worker cooperative is more extensive than what has been identified in non-worker owned firms. Effective governance, at IEM, relies on a rigorous vetting process prior to an employee’s inclusion in ownership and diverse opportunities for participation in governance. The case study concludes with a discussion of several current challenges facing IEM.