Headley came through with a storybook swing at the stroke of midnight in his Yankees debut, hitting a game-winning single in the 14th inning to give New York a 2-1 victory over the Texas Rangers on Tuesday night.
"A little chaotic. Awesome, though," said Headley, acquired from San Diego in an afternoon trade. "Mixed emotions, but I couldn't be happier."
Derek Jeter broke Lou Gehrig's franchise record for doubles, and the Yankees won an unlikely pitching duel after rookie starters Chase Whitley and Nick Martinez both entered with a 5.10 ERA.
J.P. Arencibia snapped a scoreless tie with a leadoff homer in the 13th against New York reliever David Huff, but the Yankees responded with Brett Gardner's leadoff double and Jacoby Ellsbury's tying single off closer Joakim Soria in the bottom half.
Most seats were empty by the time Brian Roberts doubled with one out in the 14th off Nick Tepesch (3-6), who threw 99 pitches over 4 1/3 innings during Sunday's start in Toronto. Roberts was held at third on Francisco Cervelli's single before Headley looped a single to left-center just as the clock struck midnight.
"Sometimes these things happen. I had a chance earlier to get it done. There's a lot of nerves, but then I thought, why wouldn't this day go this way?" he said. "I was yanking off everything and made an adjustment and shot it the other way."
Headley raised one arm as he ran to first and was soon mobbed by his happy new teammates. He was doused with a sports drink by Gardner during a postgame television interview.
"Unbelievable," Headley said after going 1 for 4. "I'm excited to be here. I can't wait to help, and just to be a part of this great franchise."
The third baseman left the Padres in Chicago and caught a flight that landed at LaGuardia Airport about 6:30 p.m. An hour later, he was in uniform shaking hands with other Yankees in the dugout during the top of the second inning.
"I was expecting to play," Headley said.
He struck out as a pinch hitter in the eighth and had a great chance to win it in the 12th when he grounded out with the bases loaded to end the inning. The 2012 Gold Glove winner also made a leaping grab to end the 10th.
"He's had a whirlwind of a day," Yankees manager Joe Girardi said. "He's a new chip for us."
Jeff Francis (1-0) worked a scoreless inning to win his Yankees debut in a game that took 4 hours, 51 minutes.
"We didn't give in. We didn't give up," Rangers manager Ron Washington said. "We didn't give them the game. They beat us."
It was New York's third walkoff win this season -- and second in three days. The team said Headley became the first player to get a game-ending hit in his Yankees debut since Roy Weatherly against the Washington Senators on April 22, 1943, according to research by the Elias Sports Bureau.
The teams combined to use 17 pitchers. Minus ailing slugger Mark Teixeira, the Yankees were held scoreless for 17 straight innings by a last-place team with the highest ERA in the American League by half a run.
Looking to upgrade that sagging lineup, New York obtained Headley from the Padres for rookie infielder Yangervis Solarte and minor league pitcher Rafael De Paula.
Jeter hit his 535th double in the ninth, snapping a tie with Gehrig. Carlos Beltran grounded into an inning-ending double play against Neal Cotts.
It was the longest scoreless game for the Yankees since they beat Boston 2-0 in 15 innings on Alex Rodriguez's two-run homer Aug. 7, 2009.
Rangers RF Alex Rios missed his third straight game with a sprained right ankle, but Washington hopes Rios will be able to play Wednesday night. Rios ran before the game and was scheduled to go through a full workout during batting practice. ... Rangers C Geovany Soto went on the 15-day DL with a strained right groin, less than a week after he returned from right knee surgery that had kept him out all season. ... Kelly Johnson started in right field for the first time in his career as Girardi rested slumping Ichiro Suzuki. Johnson made a nice running catch in deep right-center to begin the 10th, but came out with discomfort in his groin before the 11th. He was replaced by Suzuki and went for an MRI. ... Headley is wearing No. 12 with New York. In San Diego he wore No. 7, which was retired by the Yankees in honor of Mickey Mantle.
Headley Walks-Off In Yankees Debut
In his Yankees debut, Chase Headley's RBI single in the 14th lifted the Yankees to a 2-1 win over the Rangers.