Lorgh was a Klingon warrior and a family friend of Mogh. He was a member of Imperial Intelligence for much of the 24th century.
Sometime in the 2330s, Lorgh arranged to meet Elias Vaughn at Deep Space Station K-7. (TLE novel: The Art of the Impossible)
Lorgh took care of the infant Kurn while Mogh travelled to Khitomer in 2346. After Kurn's family was apparently killed at the Khitomer Massacre, Lorgh raised Kurn as his own son and did not tell him of his true parentage until he had reached the Age of Ascension. Kurn continued to pose as the son of Lorgh until the Klingon Civil War, to protect his honor after Worf accepted discommendation to cover Ja'rod's treachery at Khitomer. (TNG episode: "Sins of the Father")
In 2377, Elias Vaughn was commanding the USS Defiant and chasing Taran'atar who had kidnapped his daughter, Prynn Tenmei. Vaughn believed that she had been killed, but that Taran'atar had survived. After finding signs that a Klingon ship had been in the area, he contacted Lorgh for information. Upon heaving of Prynn's (only apparent) death, Lorgh told Vaughn that the IKS noH'Pach had been in the area and told him the class of the ship so that Vaughn could discover its specifications. (DS9 novel: Warpath)
In 2379, Worf used information that Lorgh had given him to access the secret sub-subbasement in the Federation Embassy on Qo'noS where Section 31 had a secret operations base. Before telling Worf, Lorgh was the only Klingon to know of its existence. Soon after, Worf asks Lorgh to give him any information that he could use against Councillor Kopek. Lorgh gave him a very detailed Imperial Intelligence file in exchange for the specifications of a Breen vessel that Starfleet had recently captured. (TNG novel: A Time to Kill)