The literature emphasizes the importance of structural ambidexterity in a company's ability to consistently produce radical innovation (RI). Large companies possess a multitude of resources for product development in their mainstream: laboratories; hardware; software; human competencies; and specialized organizational functions in engineering, marketing, and finance, among others. The potential of these resources is immense, and it is not rational to duplicate them for RI development; it is better to leverage them when necessary for a newstream project. However, prior research has revealed that routine rigidities can pose key obstacles to leveraging resources from the mainstream for the newstream. Such rigidities, if not addressed, can hinder RI. Further, the factors facilitating resource leverage must be better understood. Based on data from over 12 years at a leading global high-tech company, this study focuses on how companies manage to leverage mainstream resources for newstream RI projects. The emergent grounded model contributes by elucidating the enablers and constraints within the mainstream and newstream domains for leveraging mainstream resources into the newstream. Additionally, the study proposes a viable configuration of the innovation management system that effectively eases the systematic leveraging of resources from the mainstream to the newstream.