Current C2+ hydrocarbon production from fossil fuel feedstocks will in-time be replaced by alternate synthesis methods involving cleaner energy strategies. One approach is to incorporate direct sunlight during catalytic C2+ synthesis via the modified Fisher Tropsch synthesis (CO2-FTS) reaction. Light-driven studies targeting C2+ products from CO2 under high-pressure conditions are scarce. Herein, we demonstrate that direct visible light illumination can selectively boost hydrocarbon synthesis by a K-promoted Fe catalyst during the high pressure (23 bar), thermal catalytic CO2-FTS reaction. Visible light illumination imparts carrier-induced benefits to amplify CO activation and hydrocarbon synthesis. Visible light illumination modifies the surface charge of Fe. This promotes CO adsorption and C-O bond lengthening over the K-Fe catalysts, and dissociation to *C. The light-enhanced *C production boosted Fe carbide formation which facilitates FTS. Concurrently, *C hydrogenation leads to hydrocarbon synthesis. The findings offer new insight into the cascading impact of light within dynamic catalytic systems arising from the interdependence between catalyst activation and performance.