Having started the day three strokes back from the lead, Yin pumped her fist with satisfaction as she drained a birdie putt on the par-five 18, carding a four-under-par 67, before waiting for her competitors to finish in Springfield, New Jersey.
Japan's Yuka Saso (66) finished one stroke back in second place after a bogey on the par-three 16 undermined an otherwise blemish-free final round.
Yin, who collected her maiden LPGA Tour title at the DIO Implant LA Open earlier this year, is only the second Chinese woman to win a golf major.
"I would say she's definitely the goal that I'm chasing," said Yin, who was nine years old when Feng won the Women's PGA Championship in 2012. "She is the person who inspired me the most."
Yin hit every green and kept her poise through a mid-round rain delay, overcoming hiccups she experienced earlier in the tournament that saw her stumble with four bogeys in the second round.
"For the last couple days, my ball-striking was perfect. I only missed, I think, six greens in four days," she said.
"Before today's round, I just told my physio that my goal for today (was) just no three-putt. I don't care if I'm winning or not, just no three-putt. I did it, too."
She offered a subdued celebration but became emotional at the trophy ceremony as she thanked her parents for supporting her "since day one."
Saso drained her birdie putt on 18 but could only watch on as Yin equalled her effort.
"I was on the 18th tee and I saw the leaderboard, and I know I have a one-shot lead," said Yin. "After the tee shot, I saw Yuka make an incredible birdie here, and I know I have to make birdie at this hole to win the championship. I'm glad I did it."
Spain's Carlota Ciganda carded an astonishing seven-under par 64, with an eagle on the par-five seventh, to finish in a five-way tie for third place with Sweden's Anna Nordqvist, American Megan Khang, China's Lin Xiyu and Stephanie Meadow of Northern Ireland.
"I wanted to be aggressive today. I thought I could have a low round on this golf course," said Ciganda. "After the rain we had, I thought it was gettable, and I was trying to hit as many greens as possible."
American Rose Zhang (67), a home country favourite who dazzled earlier this month when she won on her pro debut on the LPGA Tour, kept her terrific year on track to finish tied for eighth in her first major as a professional.
"It's been incredible. I felt so much support and love from the crowds out here," she told reporters. "Safe to say it's super special, and I took it all in."
