Multiferroic materials are of great importance for the development of next-generation multifunctional devices. Here, we predict a stable one-dimensional (1D) antiferromagnetic (AFM) semiconductor NbI${}_3$ chain, in which moderate electron doping induces site-centered charge order, ferrimagnetism (FIM), and ferroelectric polarization. The asymmetric Jahn-Teller distortion makes adjacent Nb sites inequivalent, and the resulting charge order combines with bond dimerization generate to ferroelectricity. At 0.5 e/u.c doping, the FIM chain is half-metallic and has a calculated polarization-reversal barrier of about 13 meV/u.c. The optimized ferromagnetic configuration suppresses this asymmetric distortion and charge order, linking polarization to the magnetic configuration. Finally, considering the experimental feasibility of doping, we identify Li–intercalated bulk NbI${}_3$, i.e., (NbI${}_3$)${}_2$Li as a viable platform to realize the electron–doping effect in the NbI${}_3$ chain and the coexistence of magnetic and ferroelectric orders in this system further confirms its multiferroic nature. Our research paves a new way for the design of 1D multiferroic materials.