This article presents a counterpoint to a structuralist view of job quality and argues that it can be understood as an outcome of contested power dynamics of interest representation within institutions of labor market regulation. The article presents studies of unions in two sectors in the UK (health care and industrial cleaning) where bad jobs are common. It examines how unions have sought to regulate job quality through representing new interests within existing institutions and by extending institutional regulation to new groups. The evidence highlights the contested nature of these decisions and the importance of collective actors in exercising agency in seeking to improve job quality. The evidence shows how new interests can be promoted within institutions to (seek to) improve job quality, despite internal resistance.