Moment-resisting beam-to-column connections are pivotal in ensuring the seismic performance of steel frames. Post-earthquake reconnaissance has consistently shown that these connections are highly susceptible to damage due to premature yielding and local buckling, necessitating rigorous performance enhancements. Furthermore, evolving seismic code requirements have underscored the urgency of developing effective strategies to bolster the load-bearing capacity of existing connections. This study investigates the efficacy of a novel strengthening technique employing bent plates integrated into the beam-to-column interface to enhance seismic response. To this end, two full-scale four-bolt unstiffened extended end-plate connections were subjected to cyclic loading. The control specimen was intentionally designed with a capacity below the expected moment of the connection zone, while the second specimen was retrofitted with the proposed bent plates to compensate for this deficiency. Subsequently, high-fidelity finite element models were developed in ABAQUS, accounting for material and geometric nonlinearities, complex contact interactions, and bolt pre-tensioning. The numerical models were rigorously validated against experimental data, showing excellent correlation, and were further utilized for comprehensive parametric studies. The findings demonstrate that the application of bent plates significantly improves cyclic behavior, resulting in an approximately 40% increase in ultimate strength and a 39% enhancement in energy dissipation capacity. Notably, the reinforcement successfully relocated the plastic hinge away from the column face into the beam span. Given its structural efficiency and ease of implementation, this method is recommended as a reliable solution for strengthening beam-to-column connections and the seismic retrofitting of existing steel structures.