We report the design of a low inductance park gap switch for Blumlein-driven lasers which is highly reliable under conditions of high repetition rate and high average power. The reported spark gap has provided reproducible pulse waveforms without maintenance for 108 shots in a Blumlein-driven nitrogen laser. When operated with a nitrogen–SF6 mixture in the laser tube, this laser provided peak powers in excess of 3 MW at 5-Hz repetition rate and an average power of 0.5 W at 120-Hz repetition rate.