John T. Graham was born on December 4, 1833, in Easton, Maryland. He moved to Baltimore, Maryland, around 1848 and worked in a grocery store. He married Elizabeth Turner around 1858. Although his father was a slaveowner, Graham joined the Republican Party in the 1850s and supported Abraham Lincoln in the election of 1860. In November 1860, he wrote to Abraham Lincoln and declared his support for “Free Press, Free Speech and Free Soil.” He urged the president-elect to appoint conservative Republicans like Montgomery Blair to his cabinet.
Graham remained loyal to the Union during the Civil War, and he served as secretary of Baltimore’s Union Relief Association. He enlisted in the Union army on September 1, 1861, and he mustered in as a quartermaster in the Purnell Legion, Maryland Infantry, on September 30. He resigned in March 1862. Then, in September 1862, he played an active role in preparing the city for a potential Confederate invasion. He also played an active role in the Baltimore Association for the Moral and Educational Improvement of the Colored People.
Graham continued to support the Republican Party immediately after the war. He initially supported Radical Reconstruction and took part in a Republican Party procession in October 1866. By 1871, however, he had joined the Democratic Party. Graham worked as a merchant after the war, and by 1870, he owned $25,000 of real estate and $30,000 of personal property. By 1880, he was working as a real estate broker. He applied for a federal pension in January 1905 and eventually secured one. His wife died in October 1920, and he passed away in Baltimore on February 15, 1923.