We present a qualitative study of Agile Stage‐Gate Management (ASGM),: a hybrid new product development methodology that combines Agile and Stage‐Gate Management (SGM) approaches for the coordination of new product development. When applied to software projects, Agile is expected to deliver reduced development times, improved resource utilization, and greater financial success. We examine whether ASGM practitioners realize similar outcomes in a sample of global firms developing complex electro‐mechanical products (e.g., automobile components, railway propulsion systems, and medical devices). Our grounded theory approach articulates an understanding of ASGM through extensive interviews of experienced professionals. Our thematic analysis supports many expected benefits (i.e., speed to market, innovation enabling), but also does not encourage others, and reveals new pitfalls that deserve recognition (i.e., resource inefficiency). ASGM is not a panacea for all product development. Overall, physical product firms adopting this method can expect reduced development times and higher levels of innovation but will expend more resources to complete development projects, but a dichotomy exists. Physical product developers using ASGM experience a negative impact on project resource efficiency due to the need for dedicated resources, frequent product demonstrations, and duplicative management structures.