Kvitova didn’t put a foot wrong in a 6-0, 6-1 semifinal victory over her Czech FedCup teammate Klara Zakopalova.
Halep defeated fourth-seeded Caroline Wozniacki — a former world number one and four-time winner of this event — 6-2, 7-5.
Halep broke Wozniacki three times in each set to claim the victory in one hour and 20 minutes.
Kvitova, seeded third, needed just 50 minutes to get past unseeded Zakopalova in the semifinals of this US Open tuneup on the hardcourts at Yale University.
“I think the beginning of the match was pretty close,” Kvitova said. “Klara had chances to win the first game and the next game when she was serving. I think that was the turning point.
“I was saying to myself, I need to stay focused in the first set and play really well because I know she can come back anytime and I need to be ready for it,” added Kvitova, who had been taken to three sets in her previous three matches.
“Well, she just played fantastic tennis today without any mistakes,” said Zakopalova, ranked 33rd in the world. “I think everything was working for her, so I have to just congratulate her, wish her good luck because she was the better player today, for sure. She can beat anybody with this game.”
Kvitova, who beat Russia’s Maria Kirilenko in last year’s final, will be trying to defend a title for the first time.
The 23-year-old Czech claimed the 11th title of her career in Dubai in February.
She has never before played Halep, a 21-year-old who is enjoying a breakout season that has included her first three WTA titles.
She gained a further measure of notoriety this month when her second-round victory over Marion Bartoli at Cincinnati was quickly followed by the French Wimbledon champion’s abrupt retirement from the sport.