[citation needed] Johnston was born in Winston-Salem, North Carolina, and attended local public schools.

He graduated from the Georgia Military Academy in 1953, and then enrolled as a student at Duke University for one year before entering into the armed forces.

Johnston served as North Carolina Chairman for the Reagan/Bush reelection Committee in 1984 and a delegate to the Republican National Convention.

Johnston was an unsuccessful candidate in 1992 for the Republican nomination for the United States Senate.

In 1992, he was appointed to the Board of the Piedmont Triad Airport Authority and subsequently was elected its chairman.