© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. This paper aims to explore the mechanism of involving customers as designers and decision-makers in developing new product. This study describes results from in-depth case studies with three companies: Tokyoflash, Threadless, and LEGO. These firms are pioneers in enabling customers to engage in product design and development as both designers and decision-makers. This study is based on detailed in-depth interviews with senior managers within these firms, as well as interviews with participating customer-designers. A new Customer-Dominated Innovation Process is described, which highlights the critical role played by customer-designers and customer communities and challenges the role played by senior managers in traditional phase-review processes. In addition, the methods and key factors needed to enable this engagement are discussed. This new phenomenon challenges standard models of product development in which internal resources retain authority and expertise.