In this article, a mono-tube hydraulic energy harvesting shock absorber is proposed. The shock absorber is featured with the autogeneration where it permits harvesting waste energy with a proper asymmetric ratio of compression/extension damping force can be obtained. Using the continuity equation and including the compressibility of the oil, equations that describe the variation of the oil pressure in model chambers are derived. Then, relations that relate chambers’ pressure with the damping force, the harvested power, and the system efficiency are derived. Results illustrate the effects of frequency, amplitude, external resistance, and chambers’ size on the damping force and the harvested power. The proposed model can harvest an average power of 500 W with maximum peak of 1800 W using an external resistance of 10 Ω at input amplitude of 50 mm and frequency of 1.67 Hz. In addition, the absorber can control the equivalent damping by proper tuning of external resistance to cover the damping force requirements of most passenger vehicles. Simulations are extended to include different sizes of the same absorber to suit medium and large size vehicles. The findings of this article provide a proper guide to engineer and tailor an advanced shock absorber, which would find a wide range of engineering applications