The growing emphasis on Environmental, Social, and Governance (ESG) principles has reshaped the financial landscape, particularly in industries where profit maximization is a central objective, such as private equity. This thesis begins by exploring the evolution of private equity and the integration of ESG factors, outlining the challenges and constraints that have emerged over time. It then examines existing research on the interplay between sustainability and financial outcomes. The core analysis focuses on Ambienta, a prominent investment firm in Italy and Europe, which actively prioritizes ESG criteria in its decision-making. By investigating select companies within its portfolio, this study seeks to determine whether sustainability-driven strategies can enhance economic value.