Atkins was born at Manly's Chapel, Tennessee, in Henry County. He attended a private school in Paris, Tennessee, graduated from East Tennessee University at Knoxville in 1846, and studied law. He was admitted to the bar, but he did not practice, instead engaging in agricultural pursuits.
Atkins was a member of the Tennessee House of Representatives from 1849 to 1851. He served in the Tennessee Senate from 1855 to 1857. He was elected as a Democrat to the Thirty-fifth Congress by Tennessee's 9th congressional district. He served from March 4, 1857 to March 3, 1859, but he was not a successful candidate for re-election to the Thirty-sixth Congress.
During the Civil War, he served as lieutenant colonel of the Fifth Tennessee Regiment in the Confederate Army in 1861. He was a delegate to the Confederate Provisional Congress in November 1861. He then was elected to the First Confederate Congress and was reelected in 1863 to the Second Confederate Congress.
Following the war, he was elected as a Democrat to the Forty-third and the four succeeding Congresses by Tennessee's 7th congressional district, and then by the 8th congressional district after reapportionment. During the Forty-fifth and Forty-sixth Congresses, he was the chairman of the United States House Committee on Appropriations. He was not a candidate for renomination in 1882.
Atkins engaged in agricultural pursuits near Paris, Tennessee in Henry County. He was appointed United States Commissioner of Indian Affairs by President Cleveland on March 21, 1885, and he served until June 13, 1888 when he resigned. He was an unsuccessful Democratic nomination for United States Senator in 1888. He again engaged in agricultural pursuits, retired from active pursuits in 1898, and moved to Paris, Tennessee. He lived there in retirement until his death in 1908. He was interred in the City Cemetery.
- John DeWitt Clinton Atkins at Find a Grave Retrieved on 2009-04-21
! colspan="3" style="background: #cccccc" | Confederate States House of Representatives
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|width="30%" align="center" rowspan="1"|Preceded by
none |width="40%" style="text-align: center;" rowspan="1"|Representative to the Provisional Confederate Congress from Tennessee
1861 |width="30%" align="center" rowspan="1"| Succeeded by
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de:John DeWitt Clinton Atkins