Distance‐dependent electromagnetic radiation and electron transfer have been commonly employed in washing‐free fluorescence and electrochemical bioassays, respectively. Here, we combine the two distance‐dependent phenomena to obtain sensitive washing‐free DNA detection. Distance‐dependent surface plasmonic field induces rapid photoredox catalysis of surface‐bound catalytic labels, and distance‐dependent mediated electron transfer allows for rapid electron transfer from the surface‐bound labels to the electrode. An optimal system consists of a chemically reversible acceptor (Ru(NH3)63+), a chemically reversible photoredox catalyst (eosin Y), and a chemically irreversible donor (triethanolamine). The side reactions by O2 do not significantly decrease the efficiency of photoredox catalysis. The energy transfer quenching between the electrode and label can be lowered by increasing the distance between them. Washing‐free DNA detection permits a detection limit of ~0.3 nM in buffer and ~0.4 nM in serum without a washing step.