The optimization of an optically-pumped, flowing helium afterglow for use as a high-current dc polarized electron source with high electron spin polarization is described. The atomic electron spins of He (2\sp3S\sb1) metastable atoms created by a microwave discharge are aligned in the presence of a weak magnetic field by circularly polarized radiation from a recently developed LNA laser. The polarized outer 2s electrons are liberated in spin-conserving Penning ionization reactions with CO\sb2 and are extracted from the flow tube for polarization analysis. Polarizations approaching 90% were obtained at currents below.1 μA, falling gradually to 70% at 20 μA. Comparisons with other sources, chiefly photoemission from GaAs, suggest that for most applications requiring dc currents less than 50 μA, the flowing afterglow source is superior. Possible future improvements to the present source are also discussed.