During the 15 years since "The Civil War" ignited his career, filmmaker Ken Burns has tended to focus on well-known, unassailable American figures in his much-praised television documentaries.

  His subjects have included such icons as Thomas Jefferson, Frank Lloyd Wright, Meriwether Lewis and William Clark, Elizabeth Cady Stanton and Susan B. Anthony and even the national pastime itself in 1994's "Baseball."

But Burns' next project for PBS focuses on a lesser-known figure, a man who was once world famous but has largely faded from the pop-culture consciousness nearly a century after he made his mark by becoming the first black heavyweight champion of the world.

"Unforgivably Black: The Rise and Fall of Jack Johnson" is set to premiere Jan. 17, Martin Luther King Day, and conclude the following night. The film details the extraordinary story of the son of former slaves from Galveston, Texas.

"His story works on so many levels," Burns says. "It's not just about athletic accomplishment, it's about race and sex and freedom and a man who is determined to the live the way he wants to and is punished for it. In Jack Johnson, a lot of the themes that I've tried to focus on in my work come together in one big sandwich."

It was Johnson's title-bout victory over white boxer Jim Jeffries in 1910 that sparked the search for the "great white hope" to reclaim the title for white America. Johnson's defeat of Jeffries in what was billed as "The Battle of the Century" even sparked rioting by whites in some major cities.

Johnson had to fight prejudice in the sport of boxing just to be able to finally compete in the same ring with a white contender. But he faced more formidable opponents in law enforcement after he became a wealthy public figure.

It didn't help that Johnson maintained a flamboyant lifestyle, living the high life and consorting with white hookers at a time when black men were being lynched in some parts of the country for being "too friendly" with white women.

Johnson managed to avoid the noose, but he wound up spending nearly a year in jail after he spent a few years in Europe in exile. After his conviction of violating the Mann Act in 1913, even the prosecutor admitted that Johnson was made a scapegoat for his race and the "evil" of interracial marriage.

"They couldn't shut him down in the ring, so they shut him down in the courts," Burns says. "To turn him into an animalistic force with the Mann Act prosecution was a way for the country to deny that African-Americans were unquestionably on the way up in our society."

Johnson's boxing career never rebounded after his prison stint. Before he died in 1946 at age 58, Johnson spent his final years recounting his past glories in a Times Square sideshow.

After spending four years researching Johnson's life and particularly his legal travails, Burns is spearheading an effort, backed by Sen. John McCain, R-Ariz., among others, to secure a presidential pardon for the late boxer.

A petition was filed with the Justice Department in July, and Burns says he's hopeful that it will be granted because President Bushtes) during his term in office as Texas governor honored the Lone Star state native by proclaiming March 31, the boxer's birthday, as "Jack Johnson Day."

"We want to lift the burden off Jack Johnson but also off of ourselves," Burns says. "We are a nation of laws, and this was a case where the law was unjustly applied. It's a wrong we need to right."