Intracenter luminescence (IL) of Mn²⁺ in Zn_1-xMn _xSe (x = 0.07, 0.02) was studied under pulsed excitation by the neodymium laser second harmonic. At 4 K, the IL saturation originates from the nonlinearity of the system only at the instant of excitation, the IL decay kinetics after the exciting pulse termination depending only weakly on the pumping level. At 77 K, the decay kinetics in Zn_0.93MN _0.07Se depends substantially on the pumping level, because the migration of intracenter excitation over the manganese ions initiates up-conversion, which is a slow nonlinear process. As shown by IL decay measurements in Zn_0.98Mn_0.02Se (x = 0.02), excitation migration over the Mn²⁺ ions is insignificant even at a high temperature and under strong optical pumping.