Joseph Jenkins Mackay, Jr. was born on February 11, 1891, in Wilmington, North Carolina. Mackay served as executive secretary to Governor Locke Craig. During World War I, Mackay served as the director of military enrollment for the state of North Carolina before being transferred to Washington, D.C., for an assignment with the provost marshal general's office. In 1918, Mackay served overseas with the judge advocate general staff and the postal service. He returned to the United States in April 1919 and was honorably discharged shortly thereafter. Mackay died in Asheville on October 8, 1925.