In this study, the structural, electronic, magnetic, mechanical, and dynamical properties of the new d0–d half‐Heusler (d0–d HH) KCrSb compound are investigated using spin‐polarized first‐principles calculations. Two distinct approaches are used: generalized gradient approximation (GGA) and the modified version of the Becke–Johnson GGA (mBJ–GGA). The stability investigations reveal an energetically, mechanically, and dynamically stable d0–d HH KCrSb. The magneto‐electronic research shows a stable compound in the ferromagnetic state with a half‐metallic behavior. The half‐metallic gap is 0.9 and 1.2 eV from GGA and mBJ‐GGA, respectively. It is found that the magnetic moment of the compound is an integer and follows the Slater–Pauling rule μB. So, the d0–d HH KCrSb compound is a potential candidate for spintronic and optoelectronic devices.