Plastic pollution has become a major environmental challenge because of the persistent accumulation of plastic waste in terrestrial and aquatic environments. Although various physical and chemical recycling technologies have been developed, microbial biodegradation represents one of the most sustainable long-term strategies for reducing the environmental persistence of plastic waste. Identification of plastic-degrading microorganisms is therefore an essential step toward developing effective biodegradation technologies. In this study, microorganisms capable of degrading plastics were isolated from rice rhizosphere soil collected from a paddy field in Goyang-si, Republic of Korea. Polycaprolactone (PCL) was used as a model polymer to screen plastic-degrading microorganisms and characterize the biodegradation properties of the isolated strain. A total of 13 isolates exhibiting clear zones on PCL-containing agar were obtained, and secondary screening using PCL films identified Pseudozyma sp. GYP as the only isolate capable of visibly degrading PCL films. The early-stage biodegradation characteristics of Pseudozyma sp. GYP were investigated with a particular focus on microbial attachment, biofilm formation, extracellular polymeric substance (EPS) production, extracellular hydrolytic activity, and extracellular protein secretion. These findings provide fundamental insight into the early stages of microbial plastic biodegradation and provide a foundation for developing microbial approaches to mitigate plastic pollution.