Herein, we report ultrahigh sensitive and selective hydrogen sulfide (H2S) chemiresistive sensor using SHI irradiated cerium-based metal–organic framework (MOF)/graphene oxide composite (Ce-BTC/GO). The solvothermal synthesized Ce-BTC/GO coated on an indium tin oxide (ITO) electrode, irradiated by the 100 MeV Au+ ion at the fluence rate 5 × 1010 ions/s, 5 × 1011 ions/s and 5 × 1012 ions/s has been tested for chemiresistive sensing of H2S. As irradiated, Ce-BTC/GO was multi-parametrically tested for XRD, FE-SEM, FTIR spectroscopy, Raman spectroscopy and I-V characteristics for its structural, morphological, spectroscopic and electrical characteristics. The result reveals that the irradiation treatment greatly affects the electric characteristics of the GO, achieving dramatic conductivity modulation in the presence of H2S gas, it also creates the surface sites for the H2S absorption and hence shows excellent real-time sensing performance below the maximum residue limit established by OSHA (Occupational Safety and Health Administration). SHI irradiated Ce-BTC/GO sensor also shows excellent response/recovery time, ultrahigh reproducibility, good repeatability and stability at room temperature. The sensor allows the detection of H2S with a sensitivity of 54.70% in a concentration range of 10–100 ppm with a limit of detection 10 ppm.