The objective of this study was to investigate the economic viability and assess the sustainability of various pavement maintenance and rehabilitation strategies of flexible pavement. The major research scopes included formulation of maintenance strategies based on the Pavement Condition Index, assessment of cost-effectiveness through Life Cycle Cost Analysis (LCCA), and estimation of environmental impact through Green House Gas (GHG) emissions. At first, a flexible pavement section was designed with an analysis period of 18 years with three alternative strategies that include standalone and a combination of patching, and mill and overlay. Next, LCCA was estimated and it was found that patching at every 5 years interval, and mill and overlay at every 10 years interval offer the most cost-effective solution. Furthermore, a Life Cycle Assessment (LCA) was carried out at various stages of construction. The findings revealed that mill and overlay had the minimum GHG emission followed by the alternative that combines patching and mill and overlay. Overall, it was envisaged that the methodological framework developed in this study would help road agencies, policymakers, and other stakeholders to devise rational alternative strategies and then decide the cost-effective and sustainable solutions for flexible pavements.