An optical parametric amplifier is constructed as the short-pulse front-end of a Nd:Glass high-energy laser system. It is composed of two beta-barium borate (BBO) crystals and uses a common pump beam for a series of stages. A 532-nm pump beam of 110 mJ boosts the signal energy from 9 nJ to 7 mJ through two BBO stages. A parametric gain of similar to 10(9) and a main-to-preceding pulse contrast of similar to 10(6), using a Pockels cell (PC) for gating, are achieved without significant spectral distortion. The mJ output with these parameters is competitive for usual short-pulse frontend pre-OPA amplifiers in high-energy Nd:Glass laser systems.