GALVESTON, Texas -

Family and supporters of a local sports legend have some star power behind their push to exonerate the former boxing champion for a crime committed more than 100 years ago.

Known as the "Galveston Giant," Jack Johnson put his hometown island on the map when he became the first African American to win the heavyweight boxing title in 1908.

But a few years later, Johnson served prison time for traveling across state lines with a white woman, violating what's known as the Mann Act.

That woman was his girlfriend, who became his wife. Johnson died in 1946.

His family is now taking a push for exoneration straight to the white house in a YouTube video directed at President Obama.

Former heavyweight champ Mike Tyson and U.S. Senators Harry Reid and John McCain have also taken up the cause. Supporters hope social media can convince the President.

The U.S. Department of Justice has a general policy that it does not grant posthumous pardons, but Johnson supporters hope the President makes an exception in this case.