Harding was born in Philadelphia, Pennsylvania and learned the printing trade from the publisher Enos Bronson. After first starting his career in the office of the United States Gazette he started his own business in 1815 at the age of 16. Eleven years later, in November 1829, he purchased the Pennsylvania Inquirer newspaper from John Norvell and John R. Walker. About the same time he began printing Bibles and became the largest publisher of Bibles in the U.S.
Initially a supporter of Andrew Jackson, Harding attempted to simultaneously support Jackson while also defending the directors of the Bank of the United States, which Jackson fiercely opposed. Harding later switched support (and his newspaper's editorial stance) to the anti-Jackson faction within the Democratic-Republican Party and in 1836 supported the Whig candidate William Henry Harrison for president. After this, Harding's newspaper became an advocate for the cause of the Whig party, until it was weakened by internal divisions in 1852.
Harding also manufactured paper at a manufacturing plant in Trenton, New Jersey. Harding merged the Pennsylvania Inquirer with the Daily Courier in 1839, and for a while the paper was known as The Pennsylvania Inquirer and Daily Courier. In 1845, it was called The Pennsylvania Inquirer and National Gazette.
- "Harding Editions". Manifold Greatness: The Creation and Afterlife of the King James Bible. Folger Shakespeare Library. Retrieved 10 July 2013.