Chemically active Janus colloids - microscale particles with two distinct faces, one catalytic platinum and one inert - offer a controllable model for active fluids. Unlike Brownian diffusion, active particles exhibit out-of-equilibrium life-like motion. When placed in aqueous suspensions of hydrogen peroxide, asymmetric surface reactions generate ionic gradients that create a local electric field and drive electroosmotic slip within the electrical double layer, leading to electrokinetic self-propulsion. In this regime, the particle’s zeta potential sets the slip polarity and therefore orientation: negatively charged swimmers translate with the inert face leading, whereas a positive surface charge reverses propulsion and yields cap-first motion. This study investigates how catalytic cap size and light-controlled surface charge influence propulsion strength and orientation dynamics. We hypothesize that increasing cap area increases reaction flux and thereby strengthens propulsion, while also altering orientation dynamics through changes in near-surface flows. Further, we postulate that illumination shifts the particle’s zeta potential and therefore the magnitude and polarity of electrokinetic slip, allowing for real-time control of these active colloids. To this end, we perform microscopy experiments to investigate the motion and use in-house developed codes for quantitative analysis of the dynamics. Our results show thickness dependent shifts in speed distributions and cap-velocity alignment, and illumination allowing for modulation of motility. These findings establish experimentally tractable control of active transport through coupled tuning of catalytic geometry and surface charge, providing a framework for programmable micromotor design.