Kaljagh was a male Klingon diplomat in the 23rd century. He was married, and had three children, including a son born in the mid 2280s.

Kaljagh was a firm believer in peace between the Klingon Empire and the Federation, and in 2287, as an Ambassador, represented the Empire in peace talks with Federation Ambassador Catherine Joquel held on Starbase 49. However, Kaljagh was forced to undermine his own efforts for peace when Klingon Councillor Komor threatened the lives of his family. Along with Lieutenant Ag'hel of the IKS Terthos, Kaljagh was responsible for a number of explosions during the conference, intended to derail any progress. Regardless, Kaljagh was able to negotiate a beneficial agreement before being discovered. (TOS novel: In the Name of Honor)