The global Covid pandemic and the Third Reconstruction and renewed labor activism within the U.S. challenge us to find more humane, sustainable, and egalitarian ways of living and working. Those in the labor movement and the cooperative movement, who have been working to build union cooperatives, offer a vision for one type of more humane, sustainable, and egalitarian work. This article provides a case study, based on original author research, about the start of the union co-op movement in Cincinnati a decade ago. The author interviewed twelve people involved in the Cincinnati Union Co-op Initiative (CUCI), and triangulated findings against contemporaneous documents and two other case studies. The author views the formation of CUCI and the initial union co-ops, Our Harvest and Sustainergy, through the lens of social movement theory. Doing so identifies mechanisms critical to the success of a local union co-op movement. These mechanisms include the following: emulation – where a group of people model their work on that of others, such as the Mondragon cooperatives; social appropriation – where a group of people involved in an organization, such as a union or non-profit, with one purpose utilize the organization for a new purpose, like building a union co-op initiative; diffusion of information – such as sharing knowledge of cooperative models, funding, and legislation to wide networks of labor and social justice activists; brokerage – relying on known individuals and organizations to connect those in the union co-op movement to other potential allies and supporters; and resources, such as amassing pooled cash or property, recruiting donations and government support, and locating meeting space and expert services. The interviewees also identified some important components of their success that are not captured by social movement theory at the detailed level that might be most helpful to others looking to replicate CUCI’s success. The people and entities involved in a successful union co-op movement must be adaptable, draw on a wide variety of experts, aggregate information, and engage in long-term planning. Leadership and a substantial commitment of time to the movement by the leaders was repeatedly recognized by the interviewees as crucial to CUCI’s success.