Opportunities, that is, action possibilities for innovative business models, goods, services and processes, particularly affect idea generation, which is vital for innovation success. Capitalizing on opportunities requires complementing predominating problem‐centred innovation approaches. Despite mature knowledge on idea generation, there is still a limited understanding on how to leverage opportunities. Hence, there is a limited set of methods available that provide formalized guidance. To address this gap, we co‐developed an opportunity‐led ideation method in an action design research project with one of Australia's leading financial service providers. Thanks to this immersive collaboration, our method reflects not only the intent of researchers and existing knowledge but also the influence and needs of practitioners. Building on established opportunity sources from the literature, this method structures the idea generation stage of the innovation process into the activities initiation, immersion, investigation and integration. The method provides guidance on how to transform opportunities into ideas and presents activities, techniques, tools and roles that are important within the idea generation stage. Our research theoretically extends the understanding of opportunity identification within the front end of innovation. Moreover, it provides insights on balancing formalization and creativity within idea generation. Organizations can use the method as a blueprint to systematically and proactive sense, assess and translate opportunities into ideas.