Corporate leaders today face an impossible dilemma: pressured to embrace sustainability and social responsibility one moment and accused of being "woke" and neglecting shareholders the next. Behind this cultural crossfire lies an enduring question—what is the purpose of a corporation? This chapter argues that the answer isn't found in either extreme of shareholder primacy or sprawling ESG agendas, but in a third path: profitable problem-solving. With the Sustainability Flywheel, this chapter also provides a practical framework for business leaders and investors. Developed through a decade-long experience in investing in mission-driven companies, the Sustainability Flywheel shows how materiality, strategic alignment, and disciplined reinvestment create a virtuous cycle between social impact and financial performance.