Overview: Cross-functional integration is vital to help new product development initiatives succeed. We conducted a qualitative study of the new product development process for electrified cars with a focus on the interface between design and manufacturing. We considered engineering, business, and sociological perspectives to address cross-functional integration from different viewpoints and identified shortcomings of existing theory. We developed a new method to introduce constraints to facilitate cross-functional integration. The constraints introduced serve as stimuli for designers to consider their cross-functional counterparts’ requirements during the design process. Introducing constraints positively impacts cross-functional integration and creativity. Practitioners can use constraints with intention to steer their design processes in a purposeful direction.