A portable back support device is provided for increasing the spinal support experienced by a user of a low-back chair. The present invention comprises a winged headrest, a back support, a pair of removably attachable armrests, and an adjustable chair strap. The winged head rest and back support may be separatable and removably secured to one another, or alternatively may be may be one piece. The device has cushions of varying contour and firmness and is covered with an upholstery material. Cushioned armrests may be attached at the sides of the back support according to the preference of a user. The device is removably secured to a chair by means of an adjustable strap that fits around the back of a chair and may be tightened or loosened as necessary to affix the device.