For more than 100 years, Jack Johnson’s legend as the first black heavyweight boxing champion has been undisputed, but his legacy had been tarnished by a racially tainted criminal conviction.
His battles against white opponents, in the ring and outside of it, gave rise to “The Great White Hope” play and movie and he came to be lionized as a barrier breaker.
But the criminal conviction from 1913 that most would find abhorrent today — for transporting a white woman across state lines — haunted Johnson well after his death in 1946 and motivated politicians and celebrities for years to advocate for a pardon, however symbolic.
On Thursday in the Oval Office, Johnson posthumously found an unexpected champion: President Trump.
Although his own record on civil rights has come under question, often harshly, Mr. Trump, flanked by boxing champions and Sylvester Stallone, the actor who brought the case to his attention, signed an order pardoning Johnson.
The president called Johnson “a truly great fighter” who “had a tough life” but served 10 months in federal prison “for what many view as a racially motivated injustice.” Mr. Trump said the conviction took place during a “period of tremendous racial tension in the United States.”
Mr. Trump has often found himself in the center of fiery debates over race and sports, and civil rights in general, repeatedly admonishing N.F.L. players, a majority of them black, who have knelt during the national anthem at games to protest racism and police brutality.
Hours before he announced the pardon, he told Fox News that he agreed with the N.F.L.’s new policy requiring players to stand for the national anthem or remain in the locker room before games, saying of those who did not stand, “maybe you shouldn’t be in the country.”
The president also came under sustained criticism several months ago after making remarks sympathetic to white supremacists after a deadly rally by them in Charlottesville, Va.
“This, isolated, is a good gesture to right a miscarriage of justice,” said Stefanie Brown James, a Democratic political consultant. “However, there are a lot of current, modern-day issues that he could address as the living president that he chooses not to. I’m just personally tired of symbolism.”
Still, in Johnson, Mr. Trump found a way in one swoop of the pen to stake a claim on civil rights and rebuke his predecessor, Barack Obama, for not taking action on an issue that seemed in line with the principles of fighting injustice that he had championed.
Though other presidents passed up the chance to pardon him, Mr. Trump noted that the last resolution in Congress calling for the pardon was while Mr. Obama was in office, in 2015.
“They couldn’t get the president to sign it,” Mr. Trump said.
A spokesman for Mr. Obama declined to comment Thursday. But in late 2009, Robert Gibbs, the president’s press secretary, told reporters that the Justice Department had recommended against a pardon.
A former Obama administration official said Thursday that the Justice Department made that recommendation because it was their policy to focus on grants of clemency that could still have a positive effect on people who are still living.
In a television interview, Mr. Obama’s attorney general, Eric H. Holder Jr., had also raised the fact there was a history of domestic violence accusations against Johnson.
Johnson’s cause had attracted a range of supporters, including Senator John McCain and the filmmaker Ken Burns, who made a documentary about the case in 2005 called “Unforgivable Blackness: The Rise and Fall of Jack Johnson.” Linda Haywood, a woman in Chicago who traces her lineage to Johnson, also has campaigned for him for years and attended the Oval Office ceremony.