The 31-year-old Swiss star, seeking a record sixth title on the Flushing Meadows hardcourts, showed the form he used to win last month at Wimbledon and two weeks ago in Cincinnati by advancing in only 94 minutes.
That lifted Federer to 22-0 in night matches at Arthur Ashe Stadium before a typically raucous New York crowd.
“Being back in New York as World No. 1, it’s crazy and I enjoy it,” Federer said. “It definitely brings out the best in me. The crowds are incredible.
“For me I hope we can keep it going out here.”
Olympic champion Andy Murray, who beat Federer for London gold, battled into the second round while defending women’s champion Samantha Stosur, top seed Victoria Azarenka and third seed Maria Sharapova cruised in their openers.
Three-time US Open champion Kim Clijsters stretched her US Open win streak to 22 matches while Czech fifth seed Petra Kvitova and Chinese ninth seed Li Na also advanced on a day where rain halted play for more than two hours.
Top seed Federer broke Young in the eighth game of the match and held to claim the first set in 27 minutes and then broke him three times to claim the second after only an hour on the court.
Young delivered a final-game fightback before falling on Federer’s third match-point opportunity, after which the winner said he felt pressured at times by Young, who ended a 17-match losing streak only last week.
“There is pressure. Donald played well,” Federer said. “Obviously I am going in here as the favorite.”
Even Federer, who next faces Germany’s Bjorn Phau, can feel some first-match tension against an opponent who should fall with ease.
“All of us, even Federer, have to get a feel for the tournament,” Clijsters noted.
Britain’s third-seeded Murray, still seeking his first Grand Slam title, struggled at times in dispatching Russia’s 73rd-ranked Alex Bogomolov 6-2, 6-4, 6-1.
Murray put a scare into his supporters by clutching his left leg after a point in the fifth game of the final set but blamed the problem on cramping after being pushed throughout the match, which lasted two hours and 15 minutes.
“Struggling a little bit,” Murray said. “There were a lot of long points, especially at the beginning of the match.
“Just a little bit of cramping. I have to stay better hydrated for the next matches.”
The match began with four breaks of serve. Murray connected on only 28 percent of first serves in the opening set.
“A six or seven out of 10,” Murray said. “I didn’t serve well at the beginning but I won in three sets against a tough player.”
Next up for Murray will be Croatia’s Ivan Dodig, who dispatched Japanese qualifier Hiroki Moriya 6-0, 6-1, 6-2.
Australian seventh-seed Stosur began her repeat bid with a 6-1, 6-1 victory over Croatia’s Petra Martic.
Stosur, seeking her first title since upsetting Serena Williams in last year’s US Open final, fired 10 aces to advance in 51 minutes. Stosur won the first 19 points of her match before a double fault ended her bid for a golden first set.
“You knew you were going to lose one at some point,” Stosur said. “It did pop into my head for a split second. Then I hit the double fault and it was erased.”
Russia’s Sharapova dispatched Hungary’s Melinda Czink 6-2, 6-2.
Sharapova, who completed a career Grand Slam by winning the French Open last June for her fourth major, had not played since losing to Williams in the Olympic final but looked solid.
“I was just happy to be back on the court,” Sharapova said. “I haven’t had a match in a few weeks.”
Clijsters, playing in the final event of her career at age 29 so she can spend more time with her family, defeated US teen Victoria Duval 6-3, 6-1. The Belgian won US Open crowns in 2005, 2009 and 2010 and hopes to claim another.
“I’ve always felt very comfortable as soon as I step on the hardcourts and in New York,” Clijsters said.
“There’s a lot of positive emotions I use when I’m out here. I’ve had some good practices and I’m trying to carry that into the matches.”
Azarenka needed only 50 minutes to oust Russia’s Alexandra Panova 6-0, 6-1 while Kvitova downed Slovenia’s Polona Hercog 7-6 (8/6), 6-1.
Li, a first-round US Open loser the past two years, beat Britain’s Heather Watson 6-2, 6-3 to book a date with Aussie Casey Dellacqua.
“Maybe this year, I just was in the final Montreal and I won in Cincy, so I got a lot more confident,” Li said.