A novel hysteretic damper is designed for deployment in Chevron-braced frames of buildings to improve their seismic performance. The new damper, Torsional Hysteretic Damper for Frames (THDF), is a device that utilize torsional yielding of energy dissipating units in the shape of cylinders, which are made of ductile steel, to dissipate the imposed energy through seismic movements. The damper is distinguished by a variable, displacement-dependent post-elastic stiffness. This feature of the damper is intended to improve the height-wise distribution of story drifts and reduce the drift concentration in multi-story buildings. Following the conceptual development of the damper, derivation of force-displacement equations and other analytical studies necessary to implement the damper in practice are performed. Next, numerical studies are conducted to explore the effect of the THDF on the height-wise distribution of story drifts. The THDF was found to improve the distribution of story drifts along the height of braced frames. In the experimental phase of the research, a 1/3rd-scale Chevron-braced frame equipped with the newly-developed damper was subjected to cyclic tests, in order to verify the performance of the THDF and its force-displacement characteristics. Experimental force-displacement loops of the THDF was compared with analytical predictions and a good agreement was observed.