Ferrous ions in four-coordinate environments are common in protein structures, synthetic catalysts, and molecular magnets. The 3 d 6 configuration of high-spin Fe­(II) imparts an S = 2 ground state, whose analysis using conventional spectroscopic methods is often hindered by substantial zero-field splitting (ZFS). Herein, we provide detailed electronic-structure descriptions for [Fe II X­(Tp t Bu,Me )] (1-X; X = F, Cl, Br, I), where (Tp t Bu,Me ) − is hydrotris­(3- tert -butyl-5-methyl-pyrazol-1-yl)­borate. The three pyrazolyl N-donors of the “scorpionate” ligand facially coordinate to Fe­(II), giving idealized C 3v symmetry with the halide occupying the axial position. Although originally reported by Theopold and co-workers, this series is revisited herein using advanced experimental and theoretical tools. Ground-state transitions were probed by high-frequency and -field electron paramagnetic resonance (HFEPR) and far-infrared magnetic spectroscopy (FIRMS). Variable-temperature/-field (VTVH) 57 Fe Mössbauer spectroscopy, paramagnetic susceptibility, and VTVH reduced magnetization were also utilized. This combined approach provided complete sets of spin-Hamiltonian parameters. Interpretation using ab initio multiconfigurational calculations enabled quantification of halide-dependent magnetoelectronic effects. Jahn–Teller distortions induce a descent in symmetry from C 3v to C s in both solution and solid state. Finally, we demonstrate that the 1-X series is ionic, with the ZFS arising from combined Jahn–Teller and ligand field effects, rather than intrinsic spin–orbit coupling from the halides.