Lieutenant Johnson was a security officer aboard the Federation starship USS Enterprise.
In 2266, Johnson was a member of the landing party which transported to Metamorpha. (TOS comic: "The Peril of Planet Quick Change")
In 2267, Johnson joined Lieutenant Hadley in a search for General Kellen. (TOS novel: First Strike)
In 2268, Johnson fought the Klingons of the IKS Klolode while under the influence of (*). (TOS episode: "Day of the Dove")