In remarks at Arlington National Cemetery, he called it "a time when America needs all hands on deck."
"The tide of war is receding," Obama said. "My fellow Americans, our troops are coming home."
He spoke on a chilly autumn morning to an audience of veterans and dignitaries in the cemetery's amphitheater shortly after placing a floral wreath at the Tomb of the Unknowns.
Following the ceremony, Obama left the White House for a flight to San Diego to join in a holiday basketball game aboard an aircraft carrier -- the start of a nine-day trip that includes an Asia-Pacific summit in Hawaii and stops in Australia and Indonesia.
Obama used his Arlington speech to mark the coming transition from a nation fighting multiple wars in the aftermath of Sept. 11 to one where reviving a struggling economy is the overriding focus.
Last month, Obama announced plans to withdraw the last U.S. troops from Iraq. Between that and Obama's commencement of a drawdown in Afghanistan, he said, for many military families, "this holiday season will be a season of homecomings."
And he urged Americans to greet the returning vets with jobs and offers of help. "Let us welcome them home as what they are: an integral, essential part of our American family," Obama said.
Obama spoke a day after the Senate passed his proposal to give companies tax credits for hiring jobless veterans. "Our economy needs their talents and specialized skills," he said.
Earlier, with the aid of an honor guard, Obama placed the wreath on a pedestal in front of the marble tomb, then stood with a hand over his heart as a bugler played "Taps." A bell tolled and flags fluttered.
First lady Michelle Obama, Defense Secretary Leon Panetta, Veterans Affairs Secretary Eric Shinseki and other dignitaries watched from the side.
Obama's aircraft carrier visit is to the USS Carl Vinson, docked in San Diego. The first-ever Carrier Classic basketball game pits Michigan State against No. 1 North Carolina on board the ship. The ship is the same one from which Osama bin-Laden's remains were buried at sea following the raid in Pakistan that killed al-Qaida's top leader.
In an essay in Friday's San Diego Union-Tribune, Vice President Joe Biden and his wife Jill wrote that "because of the incredible courage of the 9-11 generation, the tide of war is receding and America is more secure than a decade ago."
"But as our service members return, many are discovering a new battlefield as they leave the military and search for civilian employment opportunities," they wrote.
Their article also made a pitch for the veterans' assistance the Senate approved on a 95-0 vote. The bill, expected to clear the House next week, also includes more counseling and job training for unemployed veterans and service members about to leave the military.
"We're taking steps to make the job search easier for veterans," the Bidens wrote.
On Thursday, Mrs. Obama announced that private companies have made new commitments to hire 100,000 veterans and military spouses by 2014 as part of her Joining Forces initiative. That comes on top of the 16,000 veterans hired since the program was announced last April, and another 25,000 in hiring commitments announced earlier.
Unemployment is particularly high among veterans of the wars in Iraq and Afghanistan. The Labor Department estimates that 12.1 percent of veterans who served in the military since the Sept. 11, 2001, attacks were unemployed in October. That compares with the national rate of 9 percent.
Among veterans under the age of 24, the jobless rate was closer to 22 percent.