A spin‐crossover iron(II) complex, fac‐[FeII(HLn‐Hx)3]Cl·PF6 (1), that exhibits stepwise spin transition and thermal hysteresis was synthesized by using the ligand 2‐methylimidazol‐4‐ylmethylidene‐n‐hexylamine (HLn‐Hx). Four complex cations (fac‐[FeII(HLn‐Hx)3]2+) and four Cl– anions associate through twelve imidazole···Cl– H bonds to give a tetrameric cubane‐like assembly, and one PF6– anion is encapsulated within the cavity of the cubane. Magnetic susceptibility measurements showed a three‐step spin transition, and the spin‐crossover profile became less pronounced as the sweep rate increased. At a sweep rate of 0.5 K min–1, the midpoint temperatures of the three steps are Tc(↑) = 131.2, 144.2, and 154.2 K in the heating mode and Tc(↓) = 116.8, 137.8, and 151.8 K in the cooling mode. The respective thermal hystereses were evaluated to be 14.4, 6.3, and 2.4 K wide.