Single-walled carbon nanotubes (SWCNTs) exhibit exceptional optoelectronic properties but suffer from limited photoresponse in the near-infrared (NIR) region. This study presents a novel composite material integrating lanthanide-doped upconversion nanoparticles (UCNPs) with SWCNTs to address this limitation. The core–shell structured NaGdF₄@NaYF₄:10%Er@NaYbF₄ UCNPs efficiently convert 980 nm NIR light into green emission (500–570 nm), which aligns with the bandgap of SWCNTs. Under 980 nm irradiation (76 mW/mm²), the UCNP/SWCNT composite demonstrated a remarkable photocurrent enhancement of over 3000% compared to pristine SWCNT films. The photocurrent gain exhibited a negative correlation with the SWCNT mass ratio, and non-volatile photoconductivity was observed. This strategy provides a viable pathway for extending SWCNT applications in NIR photodetection and non-volatile optoelectronic devices.