The 2016 U.S. Open champion, now ranked 127th, had initially been overlooked for a wildcard into the men's singles draw but was belatedly granted one after several days of outcry from fans over his exclusion.
When American wildcard Patrick Kypson pulled out injured, Wawrinka received a call late on Wednesday confirming that he had been given a place in the draw.
"It's my last Grand Slam of my career, so of course it's going to be special when I'm gonna play the match. That's for sure," the 41-year-old Swiss told reporters in Flushing Meadows on Saturday.
"I'm going to feel it. That's a no-brainer. But I'm super excited. I'm happy. I'm enjoying the fact that I have this opportunity to be here one last time."
The former world number three participated in the Australian Open, French Open and Wimbledon this year on wildcards.
Wawrinka said when he was aspiring to be a top player, he told himself he would only think about regrets after his career came to a close.
"I think I did everything possible to be the best version of a tennis player I could. I always push myself all those years, trying to give everything on the court and off the court. So with that, I'm quite in peace with myself," he said.
"I know I couldn't do it more. I know I took all the opportunity I had. Of course, I have some small regret. Of course, there is many match I would love to change the score, but at the end, like I say, I think I'm in peace with myself."
