<p>This study investigates the Darcy–Forchheimer stagnation point flow and heat transfer characteristics of Williamson hybrid nanofluid (Cu-TiO₂ -Kerosene) over a stretching cylinder under the influence of convective boundary conditions and Cattaneo–Christov heat flux. The mathematical model is formulated by considering nonlinear heat source/sink, activation energy, Brownian motion, thermophoresis and porous medium effects. Appropriate similarity transformations are utilized to convert the governing partial differential equations into a system of nonlinear ordinary differential equations. The transformed equations are solved numerically using the MATLAB BVP4C technique. The novelty of the present work lies in the simultaneous investigation of Williamson hybrid nanofluid flow with Darcy–Forchheimer resistance, Cattaneo–Christov heat flux, nonlinear heat generation/absorption and stagnation point effects over a stretching cylinder. The obtained numerical results are validated through comparison with previously published studies, showing excellent agreement. The impacts of important physical parameters on velocity, temperature and concentration profiles are examined graphically and numerically for both nanofluid and hybrid nanofluid cases. The results reveal that increasing the Darcy–Forchheimer parameter and porosity parameter reduces the velocity profile due to enhanced resistance within the porous medium. The temperature profile increases significantly with higher Brownian motion, thermophoresis and Biot number parameters, while the Prandtl number reduces thermal boundary layer thickness. Concentration distribution decreases with increasing Schmidt number, whereas activation energy enhances concentration behavior. It is further observed that the hybrid nanofluid exhibits superior thermal performance compared to conventional nanofluid, making it more effective for advanced thermal management and industrial heat transfer applications.</p>