Johnson was a security officer aboard the Federation starship USS Enterprise NCC-1701.
He was injured during a fight with the Klingons, when they attacked the Enterprise. Later, he was healed by the Beta-XII entity because the entity needed his violent thoughts. Like the rest of the crew, he was manipulated by the Beta-XII entity. (TOS: "Day of the Dove")
- Johnson was portrayed by David L. Ross. In James Blish's adaptation (Star Trek 11) the security officer is Galloway.