The portraits, executed by artist John Howard Sanden, will hang in the White House halls among other former presidents and first ladies, a statement from the White House said.
The portrait of George W. Bush depicts him standing in the Oval Office with a 1929 western painting, "A Charge to Keep," by William H.D. Koerner, hanging over his right shoulder. The former president used the same title for his 1999 memoir.
"I asked John to include it, because it reminds me of the wonderful people with whom I was privileged to serve," Bush said at the unveiling. "Whether they served in the Cabinet or on the presidential staff, these men and women -- many of whom are here -- worked hard and served with honor. We had a charge to keep and we kept the charge."
Laura Bush chose the Green Room, which she had a hand in refurbishing, for the setting of her portrait in which she wears a midnight blue gown.
"It's meaningful to me as a private person to know that these portraits will be on view at the White House, that my portrait will hang just down the hall from my mother-in-law, and that George's portrait will hang very close to his dad's," Laura Bush said.
President Barack Obama presided over the unveiling, which set aside political differences.
Obama has blamed Bush for the "mess" he inherited of a nose-diving economy and highly unpopular wars in Iraq and Afghanistan.
Just last week, Obama accused presumptive Republican presidential nominee Mitt Romney of "peddling the same bad ideas that brought our economy to the brink of collapse."
"That was tried, remember?" he told a crowd in Redwood City, Calif. "The last guy did all this."
White House spokesman Jay Carney was asked Wednesday if having that "last guy" with Obama at the unveiling ceremony would be awkward.
"Oh, not at all," he said.
Carney acknowledged "there are differences, without question, between [Obama's] approach and the approach and the policies of his predecessor. That was certainly the case when I believe President George W. Bush had President [Bill] Clinton to the White House for his portrait unveiling.
Former Bush spokesman Tony Fratto said he agreed Bush would not find the meeting awkward.
"This is not his first time at the rodeo," Fratto told McClatchy Newspapers. "I think he has a pretty mature view of politics and the people in the office and the ability to distinguish between the two."
During the unveiling ceremony, Obama and first lady Michelle Obama lauded the Bushes for making the transition between the two administrations smooth.
"One of the greatest strengths of our democracy is our ability to peacefully, and routinely, go through transitions of power," Obama said. "This is what we'll think about every time we pass these portraits -- just as millions of other visitors will do in the decades, and perhaps even the centuries to come."