Karlson was a Human male who lived on Torgu-Va in 2367. When a Tarn attack had hit the Federation Battle Station Torgu-Va, Karlson was killed. Karlson's wife had died the day before at Delta Three when a Tarn atomic weapon had detonated. They both had left behind three children. Julia Murat had described him as a good warrior.

Karlson was the descendant of the USS Verdun crewmember Karlson. (TNG novel: The Forgotten War)