Linac‐driven free‐electron lasers, new powerful synchrotron radiation sources, and advanced high‐power microwave devices will require very bright emitters of electrons to operate efficiently. By irradiating a Cs3Sb photocathode with a frequency‐doubled, Nd:glass laser, we have obtained a very high normalized electron beam brightness of over 1011A/m2/rad2. Peak currents emitted from the 1 cm2surface in 50 ns pulses ranged up to 80 A. Measured normalized emittances were between 5 and 9 &pgr; mm mrad.