Polarization‐sensitive infrared (IR) photodetection plays an important role in fiber optic communication, environmental monitoring, and remote sensing imaging. Semiconductors with quasi‐1D crystal structures exhibit unique optical and electrical properties due to their 1D carrier transport channels and large surface area‐to‐volume ratio, offering the possibility of high‐performance photodetectors with high photogain (G), polarization sensitivity photodetection. Herein, an ultra‐broadband photodetection (405 nm–10.6 µm) based on a quasi‐1D (TaSe4)2I single‐crystal nanowire is reported. The (TaSe4)2I photodetector exhibits excellent polarization‐sensitive photodetection, with a high dichroic ratio of Imax/Imin = 2.32 under 637 nm illumination. Notably, the (TaSe4)2I nanowire photodetector exhibits a competitive performance in uncooled mid‐wave infrared (MWIR) detection with a high photoresponsivity (R) of 110.5 AW−1 and specific detectivity (D*) of 4.8 × 1010 cmHz1/2W−1. Moreover, in the long‐wave infrared (LWIR) spectral range, an R of 67.6 mAW−1 is demonstrated at room temperature (RT). The (TaSe4)2I nanowire photodetector enables significant advancements for polarization‐sensitive and uncooled MWIR and LWIR photodetection.