This research focuses on the integration between functional finishing and the performance properties of polyester fabric for comfortable clothes. The effects of nanofinishing (zinc oxide nanoparticles and nano-polyurethane nanocomposite) on the ultraviolet protection properties of polyester fabric, the whiteness index, and the Kawabata Evaluation System were studied. Under the optimum finishing conditions, excellent protection (150) was achieved at lower concentrations of the nanocomposite, and zinc oxide nanoparticles individually enhanced the whiteness index (73). The results of the Kawabata Evaluation System showed that the finishing processes improved mechanical and performance properties (tensile, shearing, bending, compression, surface roughness, thermal, and hand properties), indicating that all the finished fabrics offered enhanced functionality, thermal and comfort properties. Enhanced total hand value properties (3.7 for summer and 5.1 for winter) were realized by finishing, assuming the finished fabrics were applied to men’s shirts and women’s dresses for summer and winter apparel. Scanning electron microscopy and energy disperse X-ray spectroscopy analyses showed a uniform layer of zinc oxide nanoparticles and nano polyurethane on the fiber surface. Fourier transform infrared spectroscopy confirmed the structural changes in the finished fabric.