This study examines the effects of mastication time and the addition of a plasticizer (acetyl tributyl citrate (ATBC)) on the properties of non-vulcanized polylactic acid/natural rubber (PLA/NR) blends using a factorial design, along with the impact of changing the weight ratio of the blends. The results reveal the formation of plasticized PLA (P-PLA)-based thermoplastics with enhanced ductility. ATBC functions as both a PLA plasticizer and a compatibilizer in the binary PLA/NR system. However, improving compatibility requires the exclusive use of masticated NR with an appropriate mastication time (60 min) before blending. Optimal properties are achieved at a P-PLA/NR weight ratio of 90/10, maximizing the impact strength (~35.40 J/m) and toughness (~7.21 × 10