This study proposes an innovative hybrid earth retention system to stabilize slopes for a road-widening project in Dakshina Kannada, Karnataka, India. The system combines soil nailing, geogrid reinforcement, geocell walls, and biotechnical stabilization—popular geotechnical techniques aligned with sustainable development goals. These methods were engineered synergistically to address the site-specific challenges of restoring a slope that experienced five major collapses during heavy rains, enabling both highway expansion and slope protection without disrupting traffic flow. Soil samples were collected, and laboratory tests were conducted to evaluate the engineering properties of the site soil. Boreholes were drilled at strategic locations and Standard Penetration Tests were performed. The analysis and design of the retention system employed both the Limit Equilibrium Method (LEM) and the Finite Element Method (FEM), utilizing GEO5 and OptumG2 software, respectively. A comparative analysis of these methods is presented, along with a non-linear regression model to establish correlations for soil nail parameters derived from LEM analyses. The study demonstrates the successful integration of geocell walls with soil nailing and geogrid reinforcement to support an unprotected embankment. The findings include the site reconnaissance report, reclamation strategies, and a detailed discussion of LEM and FEM analysis results, establishing the robustness and sustainability of the proposed hybrid retention system.