A study was carried out to determine the effects of graphene oxide (GO) filler on the properties of poly(ε-caprolactone) (PCL) films. A series of nanocomposites were prepared, incorporating different graphene oxide filler contents (0.1, 0.2, and 0.5 wt%) by the solution mixing method, and an in-depth study was made of the morphological changes, crystallization, infrared absorbance, molecular weight, thermal properties, and biocompatibility as a function of GO content to determine their suitability for use in biomedical applications. The infrared absorbance showed the existence of intermolecular hydrogen bonds between the PCL’s carbonyl groups and the GO’s hydrogen-donating groups, which is in line with the apparent reduction in molecular weight at higher GO contents, indicated by the results of the gel permeation chromatography (GPC), and the thermal property analysis. Polarized optical microscopy (POM) showed that GO acts as a nucleating point for PCL crystals, increasing crystallinity and crystallization temperature. The biological properties of the composites studied indicate that adding only 0.1 wt% of GO can improve cellular viability and that the composite shows promise for use in biomedical applications.