<p>This study studies the impact of thermal radiation, variable viscosity, and thermal conductivity on magnetohydrodynamic free convective flow of a Newtonian fluid within a vertical porous channel. Such flows are critical in energy systems, HVAC designs, and thermal insulation technologies. The momentum and energy equations, incorporating variable fluid properties and a transverse magnetic field, are formulated and altered into non-linear differential equations using non-dimensional analysis. These equations are numerically decoded using the Chebyshev spectral collocation method. Results reveal that increasing the radiation parameter leads to a rise in both velocity and temperature profiles, with velocity increasing by up to 21% and temperature by 17% as radiation effects intensify. Permeability of the porous medium significantly improves fluid motion and heat transfer, showing up to a 25% increase in the Nusselt number. The skin friction at the channel walls also varies notably with changes in physical parameters. The study’s novelty lies in the combined analysis of variable fluid properties and radiation in an MHD environment within a porous medium, growing previous models by offering a more realistic simulation of thermal-fluid transport. These findings furnish practical insights for optimizing thermal systems where heat and momentum transfer are pivotal.</p>