The design of a semi-active damper featuring an External Variable Orifice Damper (EVOD) has been investigated and developed, and the prototype has been characterized using a damper testing machine. The study tested various configurations of the ball valves within the EVOD, specifically at 0° (fully open), 60°, and 90° (fully closed) valve positions. For each configuration, force characteristics were measured across a range of velocities, providing comprehensive data on the damper’s behavior under diverse conditions. The study employs the modified algebraic mathematical modeling and implements the genetic algorithm optimization using MATLAB software to fine-tune the damper’s parameters, achieving optimal performance. The research highlights the EVOD’s efficacy in enhancing damping characteristics and adaptability in dynamic systems. The results underscore the potential of this innovative damper technology to improve structural resilience and control, offering significant advancements in the field of semi-active damping systems.