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