Gann was born June 6, 1878 in Lufkin, Texas. His father was a cotton farmer. He started trading in 1902 when he was 24. He was believed to be a great student of the Bible, who believed that it was the greatest book ever written. He was also a 33rd degree Freemason of the Scottish Rite Order, to which some have attributed his knowledge of ancient mathematics, though he was also known to have studied the ancient Greek and Egyptian cultures.