We propose an electronic load system with an interleaved structure applicable to DC, single-phase AC, and three-phase AC. Applying the interleaved method makes it possible to reduce voltage and current ripple, thereby reducing voltage and current stress applied to components and guaranteeing a long lifespan. The operation of the proposed electronic load is described in detail by explaining the relationship between the command value of the electronic load and the duty ratio of each switch in the interleaved structure. Adding a feedforward term to the PI controller improves the controller’s response, and the simulation results of DC and single-phase AC operation are presented. The validity of the proposed electronic load is verified through the 10kW prototype test.