Multifunctional, high-performance wearable heaters are highly desired for future human health-related applications but are generally hindered by the absence of flexibility, air-permeability, and clothes-knittability. Here, polymeric textile-based wearable heaters are constructed by decorating an MXene on the fiber surface via a simple solution dip coating technique. Alkali pretreatment of textiles enables strong interaction between the MXene and textiles through the synergistic effect of hydrogen bonds and physical rivet action. These MXene-decorated textiles (M-textiles) not only maintain the innate flexibility, comfort, light-weight and permeability characteristics of the textile substrates, but also exhibit exceptional heating performance including dual-driven energy conversion (electrothermal and photothermal), wide temperature range (40–174 °C in electrothermal and 40–204 °C in photothermal conversion), safe operating conditions (1–3.5 V for electrothermal, and NIR/FIR or abundant sunlight for photothermal conversion), and fast thermal response (reaching over 100 °C within 25 s at 2.5 V or within seconds in photothermal conversion). Impressively, the M-textiles integrate superb resistance to fire and bacteria, and a high electromagnetic interference (EMI) shielding efficiency of 42.1 dB in the X-band. These multifunctional M-textile wearable heaters are highly promising for applications in warmth-keeping, thermotherapy, deicing, heating water, EMI shielding, and antibacterial and fire protection, and are ideal candidates for future health management and protection.