[Purpose] Hemiplegia following a stroke can affect hand movement; therefore, reconstructing hand function is the most desired outcome for stroke patients. The purpose of this study was to explore the application of rehabilitation through the use of a dynamic hand splint and observes its effects on the muscle strength and functional activity of the affected hands. [Subjects and Methods] Chronic stroke patients who underwent a 3-month conventional rehabilitation using the dynamic hand splint were recruited . Evaluations (e.g., electromyography, grip and finger strength appraisals, and Fugl-Meyer assessment) were conducted before the test, and after the 1 and 3 month’s intervention. The hemiplegic hands intermediately and after the treatment to assess improvement in hand-muscle strength and functional increase of the hand movements were evaluated. Patient response to use of the dynamic hand splint was assessed using a satisfaction scale after treatment. [Results] The results for maximal voluntary contraction of the extensor and flexor muscles and wrist and finger strength showed a statistically significant increase from the pretest to after 1 and 3 month’s intervention. [Conclusion] Wearing a dynamic hand splint for home-use as a supplementary training program in addition to hospital-based rehabilitation can effectively increase the muscle strength of hemiplegic hands.