Abstract: A mobile, rehabilitative walker is configured for use outdoors on an irregular or rough support surface. The walker includes a support frame, configured for supporting a person in an upright position, having a plurality of frame members defining an open rear end and an interior space sized for receiving a wheelchair. A plurality of wheels are rotatably coupled to the support frame, and configured for multidirectional movement on the support surface. A support harness is vertically suspended from a rotatable upper rail of the support frame. A crank mechanism is coupled to the upper rail, and configured to rotate the upper rail to draw the support harness upward. The crank mechanism includes a crank handle located near the rear end of the support frame to facilitate rotation of the upper rail.