Methods of producing multiple protein products from blood-based materials including alpha-1-proteinase inhibitor, gamma globulin, albumin, and other proteins are described herein. The inventive methods include steps of: salt fractionation, chromatography, ultrafiltration, diafiltration, solvent-detergent treatment, and sterile filtration. Advantageously, the inventive methods are simple and produce alpha-1-proteinase inhibitor, gamma globulin, albumin, and other proteins in high yields. The sequence of process steps can be selected to obtain multiple products from various in-process materials, such as supernatants, pastes, chromatography flow-though, and chromatography washes.