Starch platelets of micro particle size in the range of 10–100 µm were extracted from potato by acid hydrolysis. Two types of starch-reinforced composites, one with poly(vinyl alcohol) (PVA) and the other with poly(lactic acid) (PLA), were prepared by solvent casting and hot press molding methods, respectively. Mechanical properties of the starch/PVA and the starch/PLA composites were determined, and the maximum tensile and yield strength obtained were around 19.7 MPa for 6% starch/PVA composite and around 7.2 MPa for 6% starch/PLA composite, correspondingly. The structure of both the composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis (differential thermal analysis/differential thermogravimetric analysis), thermomechanical analysis, and scanning electron microscopy. Finally, antimicrobial test was conducted to assess the potentiality of both the composites to be used for biomedical applications and only starch/PVA composite was observed to inhibit microbial growth against both a gram-positive (Bacillus subtillis) and a gram-negative (Escherichia coli) bacteria.