An actuator includes a controller, a motor and a sensor device. The controller includes a housing, and the motor includes a rotor, and the rotor includes a rotating shaft. The motor is mounted on the outside of the housing, and the sensor device includes a magnet and a sensor, the magnet is mounted on the rotating shaft of the motor, and the sensor is mounted inside the housing. The actuator has a good waterproof performance and anti-interference ability. This disclosure also relates to an electronic clutch system having the actuator.