4294. Worf

Worf, played by Michael Dorn, is a main character in Star Trek: The Next Generation and in seasons four to seven of Star Trek: Deep Space Nine. He also appears in the films based on The Next Generation. Worf is the first Klingon main character to appear in Star Trek, and has appeared in more Star Trek franchise episodes than any other character. Worf was the only character to be a regular in more than one live-action Star Trek series (While Miles O'Brien was featured in both The Next Generation and Deep Space Nine, he was not a regular cast member in the former series).

The House of Mogh was a family of high social and political rank which was for a time represented on the Klingon High Council. In Star Trek VI: The Undiscovered Country, Worf's grandfather Colonel Worf (also portrayed by Michael Dorn) appears in a role as the legal advocate of Captain James T. Kirk and Dr. Leonard McCoy after they are accused of killing Chancellor Gorkon of the Klingon High Council. He was also a member of the Klingon delegation at Camp Khitomer. Although not explicitly stated, he was intended to be Worf's grandfather.

Worf was born in 2340 on the Klingon homeworld as the son of Mogh. Five years later, his parents moved to the Khitomer colony. Worf's parents were killed during a surprise attack by the Romulans on the Khitomer outpost. The colony's distress call was answered by the Federation starship USS Intrepid. Chief Petty Officer Sergey Rozhenko found Worf in the rubble and took him in after failing to find any living relatives. Rozhenko and his wife Helena raised him on a small farm colony on the planet Gault, a world of about 20,000 inhabitants, almost all of them human. Worf also has a human brother, Nikolai, through his adoption by the Rozhenkos, with whom he often quarreled. He also spent time in his parents' native Minsk, later recommending it to O'Brien as one of his favorite places on Earth.
Worf did not take the Rozhenkos' last name, preferring to be addressed by the Klingon designation "Worf, son of Mogh". However, his son Alexander Rozhenko, who was raised by the Rozhenkos after his mother K'Ehleyr died, did use their surname. Although Worf was raised by humans, he considered himself a Klingon at heart and studied the ways of his people. As an adult, his mannerisms and personality, as well as his innate sense of honor, became more Klingon than human.
Worf's brother Kurn, barely a year old at the time of the Khitomer attack, had been left behind on the Klingon homeworld Qo'noS by his parents. Lorgh, a friend to House of Mogh (appearing only in dialog of the episode "Sins of the Father"), was charged with the care of the younger son, originally expecting Mogh's stay at the Khitomer outpost to be short-term. Lorgh adopted Kurn after the attack, but informed Klingon authorities that he had died with the rest of the family. Kurn was not revealed as being alive until both brothers were adults.
In 2357, Worf entered Starfleet Academy. He graduated in 2361 and was commissioned with the rank of Ensign, becoming the first Klingon officer in Starfleet. Although Worf took immense pride and a sense of honor from serving in Starfleet, most other Klingons shunned and belittled his choice of vocation.
In 2359, he became briefly involved with K'Ehleyr who was the daughter of a Klingon father and a human mother.