John Henry Knight was born on February 3, 1836, in Kent County, Delaware, to James M. Knight and Rebecca Scotton. His father was a self-described “Gentleman” who owned $8,000 of real estate and $7,000 of personal property in 1860. Knight graduated from Albany Law School in 1859 and earned admission to the bar a year later. When the Civil War began, Knight organized a company of volunteers, which became Company H of the 1st Delaware Infantry. Knight mustered in as a 1st lieutenant. His term of enlistment expired three months later. In the spring of 1862, he accepted a commission as a captain in the 18th United States Infantry. He took part in the Battle of Perryville, the Battle of Lookout Mountain, and the Battle of Missionary Ridge. He married Susan Clark on January 19, 1863, while on leave from military service, and they had at least one daughter. During the winter of 1863-1864, he became provost marshal general of Michigan and superintendent for recruitment, tasked with reorganizing Michigan’s veteran regiments. He remained in Detroit, Michigan, until February 1867, when the army ordered him to return to the 18th US Infantry. He provided security for railroad construction in the Wyoming and Utah Territories. Then, in 1869, he became an Indian agent in northern Wisconsin.
His wife died on June 29, 1867, and Knight married Susan’s sister Ella Clark on June 2, 1873. They had at least five children together. Knight resigned from his position as Indian agent around 1870 and resumed his legal practice. He eventually settled in Ashland, Wisconsin, where he organized the Superior Lumber Company. He joined the Democratic Party and became Ashland’s first mayor in 1887. He served as chairman of Wisconsin’s Democratic Party for several years, and he was a delegate to the 1888 and 1892 Democratic National Conventions. He died of cancer on August 22, 1903, in Watertown, Wisconsin.