This paper shows the process of optimizing the design of a heat sink structure. A heat sink is a device used to remove heat from electronic devices to improve the working capacity of the thermal system. Traditional heat sink optimization typically involves adjusting parameters such as fin size, spacing, angle, and shape of the object which is a limited exploration of design space. Topology optimization (TO) is an effective mathematical tool, wherein an algorithm distributes the material for given parameters and constraints within the design space. TO provides a greater degree of freedom while designing the heat sink to obtain the unconventional geometric design for better thermal efficiency and overall performance. Due to the advent of additive manufacturing technology, heat sinks with complex geometry can be manufactured easily. Hence, TO is used to optimize the heat transfer rate and to minimize the temperature difference for minimum pressure drop is implemented using the COMSOL Multiphysics software which uses MMA and SIMP techniques. Results of a case study show significant improvement. Case studies have been performed under different conditions. Under natural convection, the optimized heat sink at a 40% volume fraction, exhibited the lowest maximum base temperature of 3 to 4 K compared to the conventional design. The topology-optimized heat sinks for forced convection analysis continuously maintained reduced maximum base temperatures for a range of heat input values. At a heat input of 25 W, the highest base temperature of 6 K with 16% mass savings is demonstrated. The velocity profile analysis revealed that the topology-optimized heat sink facilitated better air mixing and higher air velocities in the finned region, promoting more efficient heat transfer.