The textile and apparel production and consumption generate a huge amount of solid textile waste. Mechanical recycling is one main method to recycle cotton waste; however, shredding in mechanical recycling shortens fiber length and reduces fiber quality. As a result, the application of mechanically recycled textiles may be limited. This research investigated mechanical methods to recycle post-consumer cotton textile waste and designed and developed second-life products. This study applied research through design methodology and documented step-by-step textile and product development practices to communicate the results. Using the textiles from deconstructed end-of-use garments with a high cotton content (80% or higher), combined with other materials, the researchers developed yarns, and nonwoven, woven, quilted, tufted fabrics. The researchers tested textile properties such as “yarn” tensile strength and elongation, fabric thickness, thermal resistance, air permeability, and stiffness. Using fabrics developed from end-of-use cotton waste, the researchers designed and developed high-value products such as bags, decorative textile, a hat, cell phone and glasses cases, and garments to contribute to the sustainability and circularity of cotton.