Barack Obama tried to negotiate less grey hair, he recalled, but Kehinde Wiley’s “artistic integrity” would not allow it. He tried to negotiate smaller ears but “struck out on that as well”. There was one area of concession, however: Wiley’s impulse to depict Obama on a throne, holding a sceptre or perhaps even riding a horse. “I had to explain that I’ve got enough political problems without you making me look like Napoleon!”

Kehinde Wiley: ‘Creating the portrait of Obama is a huge responsibility’ Read more

The result was a vivid official portrait that shows the 44th president sitting in a suit, without a tie, floating in vegetation and flowers. Obama was on hand to unveil it on Monday at the Smithsonian National Portrait Gallery in Washington, where the America’s presidents section was previously an exclusive club for white people painted by white people.

“How about that?” said Obama, after he and Wiley pulled down a black cloth to reveal the 84in-high canvas, watched by an audience that included former vice-president Joe Biden and donor Steven Spielberg, the Hollywood director. “That’s pretty sharp.”

The ceremony also witnessed the unveiling of a portrait of former first lady Michelle Obama, by Amy Sherald, whom the former president praised for capturing his wife’s “hotness”. Both portraits – produced after two sittings each – have sombre expressions, perhaps not entirely inappropriate in the era of Donald Trump.

Facebook Twitter Pinterest Barack Obama’s official portrait, painted by Kehinde Wiley. Photograph: Shawn Thew/EPA

The National Portrait Gallery began commissioning portraits of the president with George H W Bush in 1994 and added commissions of the first lady, beginning with Hillary Clinton, in 2006. Wiley and Sherald are the first African American artists selected. They were chosen from candidates interviewed by the Obamas at the White House, where the first couple often hung works by African American artists.

Wiley is a Los Angeles-born (in 1977), New York-based artist best known for his vibrant, large-scale paintings of African Americans. He typically portrays people of colour posing as famous figures in western art, challenging the white-dominated western canon. Some of the flowers in the background of his Obama portrait carry special meaning: the chrysanthemums reference the official flower of Chicago; the jasmine evokes Hawaii, where he spent the majority of his childhood; the African blue lilies stand in for his late Kenyan father.

Wiley said: “In a very symbolic way, what I’m doing is charting his path on earth through those plants that weave their way. There’s a fight going on between he in the foreground and the plants that are trying to announce themselves underneath his feet. Who gets to be the star of the show? The story or the man who inhabits that story?”

Obama noted that he had never had his portrait done before. The celebrated “Hope” election campaign poster was “cool”, he said, but he did not sit for it. “I don’t like posing, I look at my watch,” he admitted. “It’s pretty tortuous trying to take a photograph of me, never mind a portrait.”

Facebook Twitter Pinterest Barack Obama and Michelle Obama participate in the unveiling of their official portraits during a ceremony at the Smithsonian’s National Portrait Gallery on Monday in Washington DC. Photograph: Mark Wilson/Getty Images

Both Obama and Wiley were raised by American mothers and had African fathers who were absent, the former president noted. “But what I was always struck by whenever I saw his portraits was the degree to which they challenged our conventional views of power and privilege and the way that he would take extraordinary care and precision and vision in recognising the beauty and the grace and the dignity of people who are so often invisible in our lives and put them on a grand stage, on a grand scale, and force us to look and see them in ways that so often they were not.

“People in our families, people that helped to build this country, people who helped to build this capital, people who to this day are making sure that this place is clean at night, and serving food, and taking out the garbage and doing all the other stuff that makes this country work, so often out of sight and out of mind. Kehinde lifted them up and gave them a platform and said they belonged at the centre of American life and that was something that moved me deeply because in my small way that’s what I believe politics should be about: is not simply celebrating the high and the mighty and expecting that the country unfolds from the top down, but rather that it comes from the bottom up.”

Sherald’s portrait shows an unsmiling Michelle Obama with chin resting on right hand and an expansive white patternered dress by designer Michelle Smith’s label Milly. The final composition, based on photos that Sherald took during her sittings with the former first lady, includes the distinctive grey skin tones that mark the majority of her paintings.

Facebook Twitter Pinterest Michelle Obama’s official portrait, painted by Amy Sherald. Photograph: Shawn Thew/EPA

Obama turned to Sherald and said: “Amy, I want to thank you for so spectacularly capturing the grace and the beauty and the intelligence and charm and hotness of the woman that I love.” Michelle Obama, Sherald and the audience laughed. The president continued: “Special shout out to my man Joe Biden. An even more special shout out to my mother-in-law who, in addition to providing the hotness genes, also has been such an extraordinary rock and foundation stone for our family.”

Baltimore-based artist Sherald was the first woman to win the Portrait Gallery’s Outwin Boochever Portrait Competition. Soon after earning a college qualification in 2004, she was diagnosed with congestive heart failure. She underwent a transplant eight years later and continued to make art during her recovery.

Portrait of Obama: 'This will not tell the future ages what made him special' Read more

Michelle Obama praised the work – “Wow!” – and told the audience she was thinking of her family and young people, particularly girls and girls of colour, “who in years ahead will come to this place and 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. And I know the kind of impact that will have on their lives because I was one of those girls, and when I think about those future generations and generations past, I think wow, what an incredible journey we are on together in this country.

“We have come so far and yes, as we see today, we still have a lot more work to do, but we have every reason to be hopeful and proud.”

The gallery has one of two official national collections of presidential portraits (the other belongs to the White House) with star exhibits including George Washington (the “Lansdowne” portrait by Gilbert Stuart) and Abraham Lincoln, born 209 years ago on Monday.

Guests at the event included Obama’s former attorney general Eric Holder. Michelle Obama’s mother Marian Robinson was also present.