Mr. Clinton grew up in Hot Springs, Arkansas; Simmie Knox is self-taught and was born in 1935 in Aliceville, Ala., to a family of black sharecroppers.
"I used to chop cotton," said Knox of his sharecropper days, "Go out there early in the mornings and all of the family was out there in the field, working."
Talking about the former president, Knox said he believes Mr. Clinton "knows how it feels to have lived a certain life and to have been deprived of things... I knew the day he came into office, if I ever have the chance to paint a president, I think this is the one. Somehow I felt that."
Best known for his portraits of such celebrities as baseball legend Hank Aaron and comedian Bill Cosby, Knox was chosen to paint Mr. Clinton because the former president and first lady liked his depiction of Justice Ruth Bader Ginsberg, a Clinton appointee to the Supreme Court.
He is the first black painter to be commissioned for a presidential portrait.
"It's one of the highest honors as a portrait painter can have," said Knox, in an interview with CBS News Correspondent Joie Chen. "This is the big one!"
Mr. Clinton and Knox met just before Mr. Clinton left the White House in January 2001. Knox took dozens of photographs and discussed what the president would like to see in the portrait.
Knox said the painting of the former president uses the Oval Office as a backdrop. It is the first presidential portrait in the White House collection to include the American flag.
President Bush and his wife, Laura, are to participate in the ceremony with their predecessors.
Mr. Bush then plans to make his 18th trip as president to Missouri, a key state in this year's election, to defend the new Medicare prescription drug discount cards against attack from Democrats.
He says the program, which started June 1, marks a major step forward in ensuring affordable medicine vital to the health of the elderly. Democrats contend the cards are confusing and unlikely to yield significant savings.