The woman was identified as Alyssa Elsman, a resident of Portage, Michigan.
NY officials immediately allay fears of terrorism by releasing information that the driver of the Honda Accord, identified as Richard Rojas, a 26-year old Navy veteran has a history of arrests for drunken driving.
Police said Rojas attempted to flee but was he detained by officers and civilians who apprehended the driver.
Rojas is from the Bronx and has a history of arrests on charges of driving while under the influence of drugs or alcohol, O'Neill said.
New York Governor Andrew Cuomo and Mayor Bill de Blasio also rushed to the scene.
Police said a vehicle mounted a sidewalk just before noon, striking 23 pedestrians.
Of the injured, four were critical and three deemed very serious but were all likely to survive, authorities said.
Police said Rojas had been driving south on Seventh Avenue when he made a quick U-turn at 42nd Street and drove up the sidewalk for three blocks, passing tourist draws like the Hard Rock Cafe and the Bubba Gump Shrimp Co. restaurant.
Witnesses described a harrowing scene that started with screeching tires and ended with screams, panic and a fiery crash at one of the world's most visited sites. Shoes were scattered on the sidewalk. She bolted across the street.
"I saw the head injuries and the blood and the victims not moving; I realised... that a auto had ran into the crowd just minutes before". "I didn't know what was going on. I was scared for my life".
A fire department chief, Mark Foris, was at an unrelated elevator rescue when he saw the auto speed by.
Photographers snapped pictures of Rojas after he climbed from the wrecked auto and ran through the street before he was tackled by a group that included a ticket seller and a muscular door supervisor at a nearby Planet Hollywood restaurant.
The deceased teenager, named in media reports as 18-year-old MI tourist Alyssa Elsman, was walking with her 13-year-old sister, who was injured.
When Long went outside, she saw at least six people lying on the ground, including a woman lying face-down with blood pouring from her head. "Two of the people I saw that were really hurt. It seemed like it was trying to hit everybody", witness Annie Donahey told AFP.
"I was in shock, I was screaming", she said.
The vehicle ended up on its side in one of the world's most popular tourist attractions. "He smashed into the pole and, boom, straightaway the vehicle went on fire", Baidoo said.
The 18-year-old from Portage, Michigan, was visiting with her family when the speeding vehicle hit just before noon.
The auto hit a light pole and jumped the curb at West 45th Street and Broadway, where dozens of people were standing. Many said it came out of nowhere. "We initially thought they were filming something".
Officers there told her there was an "unknown speeding vehicle", Sciutto said.
White House press secretary Sean Spicer tweeted that Trump was briefed before NY authorities confirmed the death. The auto leaned on a lamppost and steel barriers meant to block vehicles from getting onto the sidewalk. "He didn't stop. He just kept going".