This study presents the rational design, synthesis, and characterization of poly(ε-caprolactone-ran-lactide) (CL) polymer inks with tunable printability and controllable biodegradability for 3D-printed implantable drug delivery applications. By varying the poly(lactide) (PLA) content (1–20 mol%) within the poly(ε-caprolactone) (PCL) backbone, the thermal and mechanical properties of the CL copolymers were precisely adjusted to meet both printing and biological performance criteria. Differential scanning calorimetry revealed that increasing PLA content systematically reduced the melting temperature (from 57 to 40 °C), enabling thermal modulation of printability and depot shape retention. Rheological and printability assessments conducted under optimized chamber temperature, feed rate, and extrusion pressure demonstrated excellent filament continuity, layer stacking fidelity, and shape preservation. Among the synthesized variants, CL1–CL3 maintained structural stability above 40 °C and were selected for detailed evaluation. The polymer inks were further validated through the fabrication of dexamethasone (Dex)-loaded CL (Dex-CL) depots, which achieved high encapsulation efficiency (>90%) and exhibited sustained drug release over 30 days in both in vitro and in vivo models. Notably, the lower melting point of Dex-CL3 contributed to faster release kinetics, confirming the utility of PLA content as a tunable parameter for degradation control. In vivo studies demonstrated prolonged Dex retention with minimal local inflammation, as confirmed by histological analysis. The CL polymer inks showed excellent biocompatibility and tissue integration, underscoring their potential for biomedical implantation. Collectively, these findings demonstrate that CL polymer inks provide a robust platform for 3D printing implantable drug depots with customizable degradation profiles, reliable structural performance, and immunological safety, supporting their use in sustained and responsive therapeutic delivery systems.