Former US President Obama said his portrait by Kehinde Wiley, who is known for his Old Master-style depiction of African-Americans, was "pretty sharp".
"Wow!" said Mrs Obama of her painting by Amy Sherald, another black artist, whose work addresses social justice.
Steven Spielberg and Tom Hanks were among guests at the unveiling.
"Nobody in my family tree as far as I can tell had their portrait done," said Mr Obama.
He joked that his yearbook picture was the closest he had come to such an honour.
