Layered double‐hydroxide (LDH) has been considered an important class of electrocatalysts for the oxygen evolution reaction (OER), but the adsorption‐desorption behaviors of oxygen intermediates on its surface still remain unsatisfactory. Apart from transition‐metal doping to solve this electrocatalytic problem of LDH, rare‐earth (RE) species have sprung up as emerging dopants owing to their unique 4f valence‐electronic configurations. Herein, the Er is chosen as a RE model to improve OER activity of LDH via constructing nickel foam supported Er‐doped NiFe‐LDH catalyst (Er‐NiFe‐LDH@NF). The optimal Er‐NiFe‐LDH@NF exhibits a low overpotential (191 mV at 10 mA cm−2), high turnover frequency (0.588 s−1), and low activation energy (36.03 kJ mol−1), which are superior to Er‐free sample. Electrochemical in situ Raman spectra reveal the facilitated transition of Ni‐OH into Ni‐OOH for promoted OER kinetics through the Er doping effect. Theoretical calculations demonstrate that the introduction of Er facilitates the spin crossover of valence electrons by optimizing the d band center of NiFe‐LDH, which leads to the GO‐GHO closer to the optimal activity of the kinetic OER volcano by balancing the bonding strength of *O and *OH. Moreover, the Er‐NiFe‐LDH@NF presents high practicability in electrochemical water‐splitting devices with a low driving potential of and a well‐extended driving period. An effective valence electronic perturbation strategy is proposed for tuning the electrocatalytic performance of NiFe‐layered double hydroxide (LDH) for oxygen evolution reaction (OER) through the construction of the Er‐doped NiFe‐LDH model. The theory analysis and experiment demonstrate that Er doping leads to the GO‐GHO closer to the peak in the kinetic OER volcano for NiFe‐LDH by balancing the scaling relation between *O and *OH.