Textiles offer the ideal platform to develop thermoelectric (TE) clothing for body heat harvesting and personal thermoregulation. Herein, textiles used in everyday clothing are adapted to fabricate a flexible and vertical TE device architecture. Selective laser patterning is used to create cavities for embedding bulk inorganic Bi₂Te₃ legs into a knitted polyester fabric used in next-to-skin sportswear. The device thermal design is optimized using fabric layering to accommodate longer legs up to 0.8 mm, and a flexible 3D-printed heat sink is integrated to maximize heat dissipation to the ambient. Using flexible copper foil to connect the legs with a low-temperature soldering paste, a stable and ultralow device electrical resistance (<1 Ω) is achieved, which is unprecedented for wearable textile-based TE devices. The developed prototype demonstrates power generation of up to 3.8 μW using body heat, and it provides a cooling effect of 1 °C for personal thermoregulation. Furthermore, the prototype withstands a tensile strain up to 20%, over 1000 bend cycles (at a 23 mm radius comparable with the curvature of the human wrist), and ten wash cycles, thereby demonstrating viability for TE clothing. Strategies for optimization are also presented to enable further performance enhancements using all textile-compatible processes.