John B. Kelley did not return to the DuPont Company after the war. By 1870 he worked in a textile mill and lived with his wife Josephine (born in Delaware, ca. 1846) in the town of New Castle. In 1880 John lived in Philadelphia where he worked in another textile mill.
John and his family moved back to Delaware by 1900 and lived in Wilmington. The final job John B. Kelley worked was as a janitor at the Federal building in Wilmington. John and Josephine had six children.
Kelley filed for an invalid pension from the U.S. government on 26 May 1891. His wife Josephine filed for a widow's pension from the government on 5 September 1914. It is not known if either one received a military pension.
Kelley died at Wilmington on 29 August 1914. His death certificate listed his cause of death as "apoplexy" and "old age."