This technology relates to an actuator motor with fast dynamic response capability, high torque density, high efficiency, and improved thermal and mechanical stability at high speed while minimizing weight. According to one example, an actuator motor includes a rotor shaft with an array of permanent magnets attached according to a Halbach array configuration. A stator includes windings that induce a torque on the rotor shaft when rotating magnetic fields interact with the optimized magnetic flux distributions of the magnets of the Halbach array. In some examples, the rotor shaft is hollow, reducing weight and rotational inertia, while improving ambient cooling characteristics of the motor.