A walker for use by those with limited mobility. The walker includes a seat assembly that assists the user in rising from a seated position or sitting from a standing position. The seat assembly is mounted in a frame and includes at least one gas spring mounted between the seat assembly and the frame that deflects the seat assembly while the user is rising from the seat or dampens the deflection of the seat when the user is sitting. The walker may include other capabilities and attachments, including a braking system and mountings for ancillary equipment.