A magnetic locking actuator for a prosthetic or orthotic device is provided. The actuator includes a first component including one or more magnets and a second component including one or more magnets. The first and second components are coupled to separate portions of the device. The magnets allow for adjustment of a length of the actuator to adjust an angular orientation of the first and second portions of the device. When magnets in the second component are aligned with magnets in the first component having an opposite polarity, a position of the second component is fixed relative to the first component, locking the actuator. When magnets in the second component are not aligned with magnets in the first component having the opposite polarity, the position of the second component is adjustable relative to the first component, thereby allowing adjustment of the height of the actuator.