An acoustic sensing system for detecting movement of an ultra-fast actuator in a hybrid circuit interrupter is disclosed. The system comprises a number of acoustic sensors structured to perform active or passive position sensing. For active sensing, the sensors emit sound waves toward a number of targeted portions of the actuator moving assembly and detect the positions of the targets based on acoustic signals reflected back to the sensors by the targets. For passive sensing, the sensors detect acoustic wavelets generated as a result of the moving assembly components moving during opening and closing operations. Acoustic signals can propagate through air or solids and thus the sensors can be mounted in a variety of locations within the circuit interrupter. Acoustic sensors are particularly well-suited for the circuit interrupter environment, as they are resilient to the environmental and external factors, such as dust, that can affect the performance of non-acoustic sensors.