This study has investigated a Darcy‐Forchheimer thin film flow over an extended horizontal surface with thermal radiation and chemical reaction effects. The governing time‐dependent equations have been non‐dimensionalized using similarity transformations and solved numerically using the fourth‐order Runge‐Kutta method and the shooting technique. The influence of magnetohydrodynamics, non‐uniform heat sourcing, viscous heat radiation, and chemical reactions on temperature, velocity, skin friction, Nusselt, and Sherwood numbers has been examined. Results have shown that porous media, magnetic field, and transient effects decrease the velocity profile, while thermal radiation and variable thermal properties enhance temperature distributions. Findings have indicated that the magnetic field and porosity enhance the skin friction coefficient whereas the heat transfer rate increases with Eckert number and Prandtl number. Rising the chemical reaction parameter from 0.2 to 0.5 rises the mass transfer rate by approximately 9.85%. The thermal analysis of MHD Darcy‐Forchheimer thin film flow in a porous system has been crucial for understanding heat transfer and fluid dynamics in complex environments. It helped in optimizing various engineering processes, such as cooling systems, filtration, and energy conversion, by providing insights into temperature distribution, convective heat transfer, and fluid behavior. This analysis has aided in designing efficient and reliable systems with improved performance and reduced energy consumption.