John Alexander was born in North Carolina in about 1754. He married Susana Alexander in Mecklenburg County, North Carolina on November 12, 1777. During the American Revolution he served as a private, possibly in the 10th North Carolina Regiment of the Continental Line or in the Mecklenburg County Regiment of the North Carolina for at least nine months in 1779. According to his wife Susana's later testimony, he was away in service for almost the entire length of the war, but there were not enough primary sources documenting this longer length of service for the U.S. Pension Office to allow that claim. John and Susana had at least four children together that survived him when he died in Mecklenburg County on July 12, 1805.