Recharged after a month away from the tour, the top-ranked Mexican star closed with a 2-under 70 to match Kung (67) and Cristie Kerr (66) at 15-under 273. Kerr was eliminated with a bogey on the first extra hole.
Ochoa was winless in seven starts after opening the year with six wins in nine events, including four straight.
Shanshan Feng (66) and Song-Hee Kim (69) tied for fourth at 14 under on the links-style Senator Course, part of the Robert Trent Jones Golf Trails Capitol Hill complex.
Swedens Louise Friberg, tied for the lead with Ochoa at 13 under entering the round, shot a 72 to tie for sixth at 13 under with Wendy Doolan (68), Sarah Jane Kenyon (69), Jill McGill (69) and LPGA Championship winner Yani Tseng (70).
Ochoa eagled the par-5 eighth and also had a bogey and a birdie in the round that she finished with six straight pars'eight including the playoff. She earned $210,000 for her 24th career LPGA Tour victory to push her season total to $2,591,048.