In this technical brief, we report the flow characteristics of a time-periodic electrokinetically mediated flow of generalized Maxwell fluid through a straight planar microchannel considering the interfacial slip effect on surface potential. Critical values of Reynolds number are obtained at different relaxation times where flow reversal initialization occurs in the core region of the microchannel. Thinner electrical double layer results in higher velocity amplitude, which is further amplified for apparent zeta potential. Moreover, dissimilar zeta potentials result in the asymmetrical amplitude of the velocity near and away from the walls of the microchannel at higher Reynolds numbers. The value of the volumetric flow rate oscillates with the relaxation time for the apparent and the true zeta potential.