Joshua Giddings was born in Bradford County, Pennsylvania on 6th October, 1795. He worked as a schoolteacher before studying law in Ohio. Admitted to the bar in 1821 he worked as a lawyer in Jefferson.
A member of the Whig Party, Giddings was elected to Ohio's House of Representatives in 1826. In 1831 Giddings formed a partnership with Benjamin Wade. Over the next few years both men became leading figures the anti-slavery movement in Ohio.
Elected to the 25th Congress in 1838 Giddings was forced to resign in March, 1842, after he was censured when he defended slave mutineers. However, he was promptly re-elected by his constituents and remained in Congress for the next seventeen years. Along with his son-in-law, George W. Julian, he was a leading member of the Radical Republicans in Congress.
In 1861 President Abraham Lincoln appointed Giddings as the U.S. consul general to Canada.
Joshua Giddings died in Montreal, Canada, on 27th May, 1864.