This article reports a compact stiffness controllable magnetorheological damper with a self-powered capacity. First, the structure, working mechanism, and analysis of the damper are presented. After the prototype of the magnetorheological damper, experimental tests were conducted to evaluate its variable stiffness feature and self-powered generation capability using a hydraulic Instron test system. The testing results demonstrate that its stiffness variation range can reach 70.4% when the applied current increases from 0 to 2 A. The energy generating capability of the magnetorheological damper was also evaluated using the Instron testing system under a harmonic excitation with 0.15 Hz frequency and 30 mm displacement. The testing results illustrate that the self-powered generation component can generate 2.595 W effective power, which is enough to control the magnetorheological component of the damper. The successful development, theoretical analysis, and experimental testing of this new variable stiffness self-powered magnetorheological damper make the concept of energy-free variable stiffness magnetorheological damper feasible.