When William Joseph Gantt was born on 7 October 1877, in Elmore, Alabama, United States, his father, William David Gantt, was 27 and his mother, Marie Eliza Dunlap, was 31. He married Laura Octavia Colquitt on 31 October 1897. They were the parents of at least 2 sons and 5 daughters. He lived in Dale, Alabama, United States in 1935 and Election Precinct 1 Ozark, Dale, Alabama, United States in 1940. He died on 9 June 1941, in Ozark, Dale, Alabama, United States, at the age of 63, and was buried in Grace Point Baptist Church Cemetery, Dothan, Houston, Alabama, United States.