Making her fourth professional start, the 20-year-old former Southern California player closed with a 4-under 68 at Brook-Lea Country Club for a one-stroke victory over Hurst.
Park finished at 16-under 272. She earned $22,500 to jump from 93rd to 17th on the money list with $26,206. The final top 10 will earn 2016 LPGA Tour cards.
Three strokes ahead of Hurst entering the round, Park had four birdies in a five-hole stretch on the front nine. She also birdied the par-5 10th, bogeyed the par-4 13th and closed with five pars.
Hurst eagled the 10th in her bogey-free 66. She played for the United States in the 2011 Solheim Cup.