Operational and maintenance cost of existing buildings is escalating making it tough for both the owner and the tenants. Retrofitting them with state of the art technologies help them to keep pace with amended recent code provisions and thus extending the older building stocks one more chance to live responsively. Retrofitted iconic buildings can thus retain their status in commerce driven real estate sector. It helps in reducing green house gas emission as well. World’s iconic skyscraper, the Empire State Building (ESB), has undergone an exemplary retrofit process since 2008 to reduce its energy demands. To achieve the goal of operational cost and energy consumption reduction, stiff challenges had taken care in a systematic manner to realize benefit throughout the entire lifespan of the ESB. Least disturbances to the tenant and on-site component handling strategies required precise planning. The present paper explores strategies and process adopted for retrofitting the ESB, and derived insightful guidelines towards operational cost savings and energy efficiency of existing buildings through retrofitting.