The conversion of protons to H-2 is a critical reaction for the design of renewable fuel generating systems. Robust, earth-abundant, metal-based catalysts that can rapidly facilitate this reduction reaction are highly desirable. Mn(bpy)-(CO)(3)Br generates an active catalyst for the proton reduction reaction upon photolysis at a high, directly observed H-2 production rate of 1 300 000 turnovers per hour, with a low driving force for this reaction. Through the use of FcMe(10) as an electron source, a proton source (triflic acid, 4-cyanoanilinium, or tosylic acid), and MeCN/H2O as solvent, the thermal reaction at room temperature was found to proceed until complete consumption of the electron source. No apparent loss in catalytic activity was observed to the probed limit of 10 000 000 turnovers of H-2. Interestingly, a catalytically competent complex (Mn(bpy)(2)Br-2), which could be isolated and characterized, formed upon photolysis of Mn(bpy)(CO)(3)Br in the presence of acid.