This paper addresses the application of green practices in existing buildings from a triple bottom line perspective. It describes the most widely used benchmark for assessing green practices, the U.S. Green Building Council’s LEED Rating System, and provides a “road map” for pursuing LEED certification. It concludes with a consideration of the triple bottom line, highlighting the economic, environmental, and social benefits of implementing green practices in existing buildings. The broad umbrella of green practices includes a wide range of applications. It encompasses developing high-performance buildings utilizing cutting edge technology to implementing management strategies in existing buildings that result in improvements to the economic, environmental, and social bottom lines—the triple bottom line. As the built environment of cities is largely old construction and not “green” by design, the benefits of green buildings remain largely untapped. It would not be practical to tear down all existing buildings and erect in their places high-performance structures. However, that does not mean the advantages of green practices remain outside the grasp of any real estate owner. By taking a broader, triple bottom line approach to managing existing buildings, building owners acknowledge the interconnections between building performance, environmental impacts, and tenant health and well-being. While many benefits of utilizing green practices in existing buildings are easily identifiable in terms of economic gains, ignoring less tangible benefits such as indoor air quality and thermal comfort creates a barrier in realizing a building’s maximum potential. The U.S. Green Building Council’s LEED (Leadership in Energy and Environmental Design) Rating System for Existing Buildings provides a comprehensive approach to building evaluation which incorporates the economic, environmental, and social bottom lines. This paper details how green practices affect the triple bottom line through case studies and an analysis of current literature.