The ceremony Friday on Singing River Island just south of Northrop Grumman Shipbuilding's facility in Pascagoula drew about 3,000, who watched as Mrs. Obama cracked the bottle on the bow.
Mrs. Obama praised Capt. Dorothy C. Stratton as a pioneer.
"I stand in awe of her life," said Mrs. Obama, the ship's sponsor. "She taught us what is possible when people are given an opportunity."
Construction of the cutter began in July 2009. The new ship has two hangars and a large flight deck. It will be delivered to the Coast Guard next summer.
The ship patrol waters off northern California on two-month missions, and can deploy two helicopters and smaller boats.
Stratton was a public school teacher and later an assistant college professor at Purdue University before she joined the Coast Guard and served as director of the women's Reserve during World War II.
Stratton, whose father was a Baptist minister, didn't come from a military family, Mrs. Obama said.
"What happened? Pearl Harbor was bombed and her country was at war and she volunteered," said Mrs. Obama, who was joined at the ceremony by Homeland Security Secretary Janet Napolitano.
As director, Stratton oversaw more than 10,000 enlisted women and 1,000 commissioned officers. Mrs. Obama said Stratton didn't have the authority to give men orders and at the time women couldn't serve overseas.
She said Stratton knew "all she had was the power of persuasion. She traveled the country giving speeches, recruiting other women. And, for the first time, African-American women."
She received the Legion of Merit for her service and left the Coast Guard in 1946, shortly before the unit she headed was demobilized.
Stratton died in 2006.
Napolitano commended the Coast Guard for its role in protecting the nation and putting "themselves in harm's way in the course of their duties."
Napolitano also said the Coast Guard should have the resources necessary to do its job.
"Stratton represents and reflects our commitment to achieve that goal ... to constantly innovate and evolve our maritime capabilities," Napolitano said.
The steel cutter cost between $600 million and $700 million, said Margaret Mitchell-Jones, Northrop Grumman's director of public affairs. It is the third of eight that will be built.
Earlier Friday, Mrs. Obama and Napolitano met privately with Coast Guard members who had been responding to the BP oil spill. Obama said she wanted to know how the Guard members were holding up under the rigors of their duties and separation from their families.
The disaster caused after the explosion of the Deepwater Horizon rig has been ongoing for about three months. Mrs. Obama said many Guard members are reservists and they've been away from their families the entire time.
Coast Guard Cmdr. Jason Merriweather the crew welcomed the break from their oil spill duties to meet the first lady and Napolitano.
"Even if it's just for an hour," Merriweather said.