He was the son of Worf and the husband of Kassin. Mogh was the father of Worf and Kurn. He would become a Grandfather to Alexander as well as Kurn's daughters. Mogh was a member of, and later the leader of the House of Mogh.
Mogh's father Worf had been a defense attorney who did not become a warrior, instead choosing to become an attorney whose battlefields were the Klingon courts. Mogh however did become a warrior at his father's urging. By 2333 Mogh was married to Kassin. His father held high hopes that the marriage would soon be fruitful and provide the family an heir. Mogh and Kassin would produce an heir in 2340, whom they named Worf after Mogh's father. A second son named Kurn would be born in 2345.
Soon after Kurn's birth Mogh's friend Lorgh gave Mogh an assignment to track down a traitor who was working with the Romulans against the Imperial government. Mogh soon tracked this traitor to the Khitomer Colony. Mogh and Kassin left Kurn with Lorgh in case the worst happened so that the survival of the House of Mogh.
Mogh and Kassin died along with nearly 4,000 other Klingons when the traitor - his rival Ja'rod - provided the shield codes to the Romulans. The Romulans were able to destroy the colony, leaving on a handful of survivors. Worf survived the attack and was adopted by a Federation Starfleet officer. Kurn was raised by Lorgh as his own son.
In the 2360s the Klingon High Council learned that the traitor was Ja'rod. Ja'rod's House, led by his son Duras was so powerful that the council decided not to put the blame on Ja'rod, fearing a civil war if they did. The council decided to instead blame Mogh. Worf and Kurn returned to Qo'noS to clear their father's name. With Duras still alive the council was unwilling to clear Mogh's name at the time. It was not until Chancellor K'mpec's successor Gowron was installed that the Empire finally cleared Mogh's name.
- Mogh was never seen on screen. An image of Mogh was created for the Star Trek Customizable Card Game that combined the features of both Worf and Kurn.