The Copper thioglycolate (Cu-TG) functionalized poly(ε-caprolactone) (PCL) was successfully prepared using the newly synthesized Cu-TG initiator by ring opening polymerization (ROP) technique. The structure of the prepared polymer was confirmed with the help of reliable analytical techniques like FTIR and NMR. The particle size and surface morphology of Cu-TG functionalized PCL were critically examined by AFM and HRTEM. The microstructure of the nucleated crystals in the PCL matrix was investigated using the polarized optical microscope (POM). The crystallization and thermal degradation behaviour of PCL under non-isothermal condition were analysed by DSC and TGA techniques. The thermal stability of Cu-TG functionalized PCL was increased while compared with pure PCL. Ozawa and Avrami exponents suggested the spherulitic growth of Cu-TG functionalized PCL. The crystallization rate and the energy of activation (Ea) under non-isothermal condition were determined using various kinetic models.