Analysis generated for the research project on Young Workers and the Labor Movement highlighted the need for innovative leadership development if young workers are to be integrated into an increasingly diverse workers’ movement, and unleashed to provide leadership in established institutions that face a radically changing economy and workforce. We examine one successful leadership development program: the New York State AFL-CIO/Cornell Union Leadership Institute. We look at the theoretical underpinnings, development, and outcomes of this multi-union, multi-sector program over the past 17 years, note its impact on the New York regional labor movement, and analyze the key factors accounting for the program’s successful development of innovative-minded young labor leaders. Those factors venturing beyond the traditional “skill-building “ approach of most labor leadership training toward a more transformational model of leadership development; an emphasis on experiential learning, using a variety of learning modes; providing a safe space and what Kurt Lewin describes as “a community of practice” where difficult challenges can be tackled collectively; and using leadership development as a tool to build inclusion and solidarity across many dimensions of difference, including age, race, gender, ethnicity, sector, able-ness, education level, industry, and more.