Integrating multiple functions into fabrics has provided attractive opportunities for smart wearable technologies. However, it remains challenging to achieve functionalities with fabrics through a facile green pathway suitable for industrialization. Herein, we demonstrate a facile metal-free and solvent-free route to endow commercial fabrics with unified functions utilizing hydroxyethyl cellulose (HEC) and carbon black (CB) via facile dip-coating. Based on the superior compatibility of HEC and CB, incorporating trace amounts of CB (as low as 0.25 wt %) triggers remarkable photo/electro-responsive thermal conversion with rapid responsiveness, appropriate temperatures, and reliable repeatability, verifying wearable heating performances of the modified fabrics. Notably, the resultant fabrics serving as a tribopositive material of triboelectric nanogenerators harnessed electrical signals from minute movements to deliver an open voltage of 321 V, a short current of 3.84 μA, and a transferred charge of 9 nC, and eventually achieved a maximum instantaneous power density up to 2067 mW/m2, showing a significant improvement of 28.2 times higher than that of the original fabric. Furthermore, the fabric-based TENGs effectively deliver instantaneous feedback on human motion and gait analysis, which exhibits good application prospects for detecting and optimizing body postures. The eco-friendly and effective methodology drives the facile and sustainable conversion of commercial fabrics toward wearable healthcare applications.A facile solvent-free and metal-free strategy is developed to efficiently convert commercial fabrics into cellulose-based smart wearable systems capable of wearable energy harvesting, body motion detection, and photo/electro-responsive thermotherapy.