This study evaluated the laboratory and field performance of an asphalt mixture incorporating 50% reclaimed asphalt pavement (RAP) and an epoxidized soybean oil-based rejuvenator. A 12.5-mm dense-graded asphalt mixture was designed using a balanced mix design (BMD) framework to determine the optimum rejuvenator dosage based on the Indirect Tensile Asphalt Cracking Test (IDEAL-CT) for cracking and the Hamburg Wheel-Tracking Test (HWTT) for rutting performance. Laboratory testing indicated that the rejuvenator substantially improved cracking resistance while maintaining rutting performance within acceptable limits. The optimized mixture containing 4.1% rejuvenator was produced in an asphalt plant and placed at the National Center for Asphalt Technology (NCAT) Test Track for monitoring under heavy truck traffic and warm climate conditions. After approximately 5 million equivalent single axle loads (ESALs), no visible surface cracking was observed, and rut depth remained below 3.6 mm. Ride quality, measured by the international roughness index (IRI), stayed stable at 1.0–1.2 m/km, while surface texture, expressed as mean profile depth (MPD), gradually decreased from 1.2 mm to 0.7 mm due to normal aggregate polishing under heavy truck traffic. These early findings demonstrate the potential of the bio-based rejuvenator to maintain satisfactory field performance in high-RAP asphalt mixtures.