The generation of a high-quality electric power supply to meet the load demand and maintain the power balance with the load demand plays a crucial role in generating units. This crisis is overcome by implementing the power network’s load frequency control (LFC) scheme to keep the system stable and improve the quality of the power supply delivered to consumers. In this work, an interlinked hydropower plant is considered with a proportional-integral-derivative controller (PID) as a subordinate controller for performance enhancement of the investigated power system. The parameters of the controller are optimized via the ant colony optimization (ACO) algorithm with an integral time absolute error (ITAE) as the objective function. The proposed method is compared with a genetic algorithm (GA), and particle swarm optimization (PSO)-tuned controller response for the same power system shows its supremacy. The robustness of the proposed method is examined by considering system parameter variation and load disturbance. The evaluation of the simulation results reveals that the ACO-tuned PID controller achieves a faster settling time with minimal overpeak shoots.