Wearable assistive, rehabilitative, and augmentative devices require bulky and heavy power supplies, often making these tools more of a burden than an asset. This work demonstrates a soft, low-profile, and comfortable textile-based energy harvesting system. Pneumatic energy is harvested with a textile device integrated into a shoe insole, and pneumatic energy is stored in a flexible textile wearable, enabling users to produce and store the power needed to operate a range of pneumatic actuators. A maximum average power of nearly 3 W with a remarkably high efficiency (recovering more than 20% of the mechanical energy expended during walking) was harvested. The system was fabricated using a state-of-the-art stacked laminate assembly of textiles. To optimize our system, a mechano-fluidic model was developed and validated against experimental results. The use of our system is demonstrated in powering a textile-based assistive device as well as a supernumerary arm used to augment human capability.