Mallory Hytes Hagan, 23, scored in the talent competition with a tap dance to James Brown's "Get Up Offa That Thing," and wowed judges with an unadorned, off-the-shoulder white evening gown.
"Oh, my God, thank you!" Hagan, from Brooklyn, said as she was crowned at the end of the two-hour live broadcast from Las Vegas' Planet Hollywood Resort & Casino on ABC.
The first runner-up was South Carolina's Ali Rogers, followed by Alicia Clifton from Oklahoma, Wyoming's Lexie Madden and Miss Iowa, Mariah Cary.
Montana's Alexis Wineman, who has spoken about having been diagnosed with autism when she was 11, was chosen by fans online and made it to the semifinals. Fourth runner-up Cary discussed having Tourette's syndrome.
The judging panel, which included teenage Olympic gold-medal gymnast McKayla Maroney, "Dancing With the Stars" dancer Cheryl Burke, former Miss America Katie Stam Irk, former "Entertainment Tonight" host Mary Hart and ABC weatherman Sam Champion, was permitted to return one eliminated contestant to the semi-finalists' pool. They chose Washington's Mandy Schendel.
In the competition's final segment, each of the five finalists answered a question about current events. Hagan was asked whether, in the wake of the Newtown school massacre, armed guards should be put in schools.
"I don't think the proper way to fight violence is with violence," she said, indicating she opposes the idea.
Hagan, whose crown comes with a $50,000 college scholarship, said education and other measures such as extended waiting periods for gun ownership were more appropriate.
The pageant, held since 1921, is put on by the Miss America Organization.
Contestants compete in local and state pageants before going on to the national competition. In all, 53 women representing the 50 U.S. states, the Virgin Islands, Washington and Puerto Rico vied for the title.
(Reporting by Chris Michaud in New York; Editing by Xavier Briand)