We sought to portray how collective bargaining contracts promote public health, beyond their known effect on individual, family, and community well-being. In November 2014, we created an abstraction tool to identify health-related elements in 16 union contracts from industries in the Pacific Northwest. After enumerating the contract-protected benefits and working conditions, we interviewed union organizers and members to learn how these promoted health. Labor union contracts create higher wage and benefit standards, working hours limits, workplace hazards protections, and other factors. Unions also promote well-being by encouraging democratic participation and a sense of community among workers. Labor union contracts are largely underutilized, but a potentially fertile ground for public health innovation. Public health practitioners and labor unions would benefit by partnering to create sophisticated contracts to address social determinants of health.