The increasing integration of distributed energy resources (DERs) into power grids has significantly altered the conventional electricity network dynamics. This paper systematically examines the role of DERs in enhancing grid stability, exploring their impact on frequency regulation, voltage control, and grid resilience. A comprehensive analysis of control strategies, energy storage solutions, and grid modernization techniques is provided. The study also highlights challenges such as intermittency, grid congestion, and cybersecurity threats. Finally, recommendations for policymakers and grid operators are proposed to ensure a stable and efficient power system.