Oliver James Dickey was born on April 6, 1823 in Old Brighton, in Beaver County, Pennsylvania, where his father, John Dickey, was postmaster and later sheriff. The older Dickey also served in the State senate and was a Whig member of the U.S. Congress in two terms during the 1840s. The son began his education at Beaver Academy before entering Dickinson College in 1839 with the class of 1844. He left his course in 1843 before graduating, and took up the study of law in Beaver, Pennsylvania with James Allison, who himself had served in Congress twenty years before.
Dickey was called to the Pennsylvania bar in 1844 and moved to Lancaster, Pennsylvania where he became for a time, until 1857, a law partner of yet another congressman, the renowned Thaddeus Stevens. He was elected the district attorney of Lancaster County between 1856 and 1859. At the outbreak of the Civil War he helped organize and served as lieutenant colonel of the 10th Pennsylvania Volunteers, a ninety day unit mustered in on April 20, 1861 and out on July 31, 1861. He also was involved in other militia units raised temporarily during the conflict. When Stevens died, Dickey was selected in December 1868 to fill the short remainder of his term, and, in a coincidence of timing, was on the same day elected as a Republican to the following Forty-first Congress. He was reelected and served until March 1873. He was not a candidate in late 1872 and his seat was taken up by A. Herr Smith, a fellow Republican and Dickinsonian. He resumed his practice in Lancaster. In his political career he attended fifteen state and two national conventions, including the Chicago meeting that nominated Lincoln. In business, he was a founder and owner of a cotton mill and president of a hose company in Lancaster.
Dickey had married in 1857 Elizabeth Shenk of Lancaster County and the couple had four children. Oliver James Dickey died at home on April 21, 1876 and is buried in Woodward Hill Cemetery in Lancaster. He was fifty-three years old.