Barack Obama's portrait was painted by New York-based artist Kehinde Wiley, who is known for his large-scale, old-master style paintings of African Americans. Baltimore-based artist Amy Sherald was commissioned to paint Michelle's portrait.
Sherald and Wiley are the first black artists to be commissioned by the Smithsonian to paint a president or first lady. Prior to their portraits, only one other African-American artist had ever painted a presidential portrait.
Read more: Barack Obama's record is a legacy under threat
Symbolic flowers in Obama portraitIn his life-sized portrait, Obama is portrayed seated on a wooden chair, surrounded by lush greenery dotted with bursts of flowers.
The flowers symbolize important influences in the former president's life: jasmine for his home state of Hawaii, African blue lilies for his late father, and chrysanthemums for Chicago, the city where he kick-started his political career.
"I tried to negotiate less gray hair and Kehinde's artistic integrity would not allow him to do what I asked," Obama joked at the ceremony. "I tried to negotiate smaller ears — struck out on that as well."
He said it was a "joy" to work with Wiley and described the artist's work as taking ordinary people and lifting them up by painting them in grandiose settings.
"In my small way I believe that is what politics should be about," Obama said. "Not simply celebrating the high and the mighty."
Read more: Dream team Barack and Michelle Obama seal landmark book deal
Michelle hopes portrait will inspire girlsMichelle's portrait depicts the former first lady in tones of white, black and gray on a blue background. The only touches of color are at the bottom, in the red, yellow and pink on her gown's hem.
The former first lady said she hopes the portrait will help inspire young girls of color in the years to come.
"They will look up and they will see an image of someone who looks like them, hanging on the wall of this great American institution," she said. "I know the kind of impact that will have on their lives, because I was one of those girls."
Barack Obama praised Sherald for capturing the "grace and beauty and intelligence and charm and hotness of the woman that I love."
The National Portrait Gallery's tradition of commissioning presidential portraits is relatively new, beginning with former President George H.W. Bush. The other portraits in its collection were either purchased or given as gifts.
Artist Simmie Lee Knox became the first African-American ever to be commissioned to paint a presidential portrait, when he painted former President Bill Clinton and his wife Hillary Rodham Clinton's official White House portraits which are separate from those which hang in the National Portrait Gallery.
rs/kms (AP, dpa, Reuters)