Corporate social responsibility (CSR) has become a relevant aspect of business in the past couple of decades as society now understands that businesses are responsible for more than just profits and shareholder value. With this increased power has come rising public expectation and demand for companies to address their impacts on society and contribute to the common good. We will provide a detailed overview of corporate social responsibility legal theory and rationale. It examines the historical evolution of CSR, the different theoretical lenses through which CSR has been understood, and the tension between voluntary and mandatory forms of corporate governance that has shaped the debate over CSR over time. It in addition explores the complex relationship between CSR and sustainable development, highlighting the necessity of proper corporate governance to reconcile these two important concepts.