Abstract Packaging materials have been developed using Capsosiphon fulvescens (CF), which is an underutilized green alga, and Capsosiphon fulvescens polysaccharides (CFPS). Persimmon leaf extract (PLE) was added to the films as an active material and the physicochemical properties of the films were examined. There were differences in the physicochemical properties between CF and CFPS films and the incorporation of PLE affected the properties of both films. The CF films had better mechanical properties and darker color than CFPS films due to different chemical compositions, and both films showed increased flexibility with the addition of PLE. In addition, the incorporation of PLE into the CF or CFPS films increased antioxidant activities. The microstructure of the films indicated that the CF films had a slightly rougher structure than the CFPS films and the addition of PLE made the films rougher. The CF or CFPS films could be used as packaging materials, and PLE could be used as a natural antioxidant to develop a food usable antioxidant film.