GREENSBORO, N.C. — First lady Michelle Obama visited North Carolina Wednesday to drum up swing-state support for her husband's re-election bid.

As part of her "It Takes One" initiative, which she launched last week, Obama called on supporters to encourage friends and neighbors to volunteer in the election and get to the polls in November.

"We are going to need every single one of you to join us," she told the cheering crowd of 2,400 at the University of North Carolina at Greensboro.

"It takes just one voice to change a room, and if a voice can change a room, it can change a city, and if it can change a city, it can change a state, and if it can change a state, it can change a nation," she said. "That is the power of one person stepping up to move this country forward."

President Barack Obama has been trying to move the nation forward for years, his wife said, recounting his efforts to rebuild the U.S. economy in the wake of the worst recession in decades, to improve health care options for millions of Americans and to expand higher education funding to create opportunities for more people.

"He believes that, when you work hard and you've done well and walked through the doorway of opportunity, you do not slam it shut behind you," Michelle Obama said. "You reach back, and you give other folks a chance to succeed as well."

The presidential election – now less than 100 days away – presents a choice for the nation's future, she said, noting that her husband plans to continue his policies aimed at helping the majority of Americans instead of a select few. The Obama administration has cut taxes for working families by $3,600 and has reduced taxes 18 times for small-business owners, she said.

"In the end, it all comes down to who you are and what you stand for," she said. "Elections are always about hope. ... They're about our hopes for our children. They're about the world we want to leave for our next generation."

The post-Summer Olympics appearance is Michelle Obama's first trip to the state since May, when she spoke at commencement exercises at North Carolina A&T State University.

"I felt she did a really good job of giving you some highlighted points but then also some details about it," Stephanie Woodbeck said of the first lady's Greensboro speech. "'Here's how you can speak to other people.' I found that to be really useful."

As part of an effort called "9-3-1," North Carolina volunteers who give nine hours or three shifts to the Obama campaign are guaranteed a seat to hear the president accept the Democratic nomination for a second term on Sept. 6 at Bank of America Stadium in Charlotte.

Michelle Obama headed to Raleigh after her UNC-Greensboro appearance for a private fundraiser at the Raleigh Marriott City Center, where tickets started at $250. It was unclear how many people attended.

Before the fundraiser, she stopped at the Obama campaign office in Raleigh to deliver some fresh fruit and energize the volunteers.

"I just dropped by," she said. "I hope you were busy."

Both the Romney and Obama presidential campaigns have made trips to North Carolina, specifically to its third largest city. In July, Ann Romney was in Greensboro stumping for her husband.