This work investigates the effect of Joule heating and viscous dissipation due to electric double layer (EDL) and electroosmotic effect on steady fully developed electromagnetohydrodynamic flow in a porous microchannel. Dimensionless formulations of the Poisson–Boltzmann, momentum, and energy equations are derived for the electric potential, velocity profile, and temperature distribution in the microchannel. Exact solutions for the temperature distributions and velocity profiles were obtained using the method of undetermined coefficients. The Debye–Hückel linearization is used to get an exact solution for the electric potential. The results showed that the Brinkmann number , Joule heating parameter , Debye–Hückel parameter , Hartmann number , electric field , and suction/injection parameter have a substantial impact on flow formation and heat transfer. Using MATLAB software, graphical simulations are provided to deliver a greater understanding of the influence of relevant parameters on the results achieved.