John B. Murray was born in North Carolina in about 1758. According to his wife, he served as a private in the Rowan County Regiment of the North Carolina Militia on a three-month expedition against the Cherokee in present-day McDowell County in 1776. He married Rosana Murray in July 1776 and the couple would go on to have at least eleven children together. He later served an additional three-month tour as a private under Colonel Charles McDowell. On May 1, 1781 he enlisted as a sergeant in a mounted unit of either a North Carolina Regiment of the Continental Line or, more likely, the 2nd South Carolina Regiment of State Dragoons and saw combat at the Battle of Orangeburgh in July of that year. After that battle, he fell sick and his wife Rosana had to come to Orangeburgh, South Carolina to help nurse him back to health. He recovered and received his discharge on February 2, 1782.

After the war, John B. Murray resided in Burke County, North Carolina and is listed on land grants as owning 50 acres on Cane Creek and 100 acres on Drowning Creek in that county. Census records indicate that sometime after 1810 and by 1820 he and his family moved to Union County, Illinois. He there died on January 31, 1828.

When his wife went to apply for a widow's pension, John B. Murray's military service was called into question by the U.S. Pension Office. Because he spelled his name variously as "Murray" and "Murry," and because he did not always use his middle initial, it was difficult to prove his military service using archival records. Eventually the pension office credited him with just six months of service as a private in the Camden District Regiment of the South Carolina Militia, much less than his wife Rosana claimed he had served.