In 2293, Worf represented Captain James Kirk and Dr. Leonard McCoy when they were put on trial on the planet Qo'noS, in suspicion of involvement in the assassination of Chancellor Gorkon. While Worf was powerless to prevent the pair being convicted in what was essentially a show trial, he nonetheless managed to convince a trio of judges who were presiding over the case that the evidence was not strong enough to support the death penalty. He noted that Gorkon's assassins could have merely been wearing Starfleet uniforms rather than being members of Starfleet themselves. Due to this line of deliberation, combined with the closeness of an impending peace summit, the sentence was commuted to a lifetime's imprisonment on Rura Penthe.
Worf was later a member of a Klingon delegation that accompanied Chancellor Azetbur to Camp Khitomer, where the peace conference was to be held. Shortly after the event began, he unmasked a disguised Klingon sniper and discovered that this assassin was, in fact, Colonel West. (Star Trek VI: The Undiscovered Country)
In the fifth draft script for Star Trek VI, Colonel Worf is characterized as a "young, eager Klingon defense attorney." The same script draft also describes the character as initially sitting, though he is consistently seen to be standing in the film. The wording of his objections during the trial is also slightly different from how they are phrased in the movie. At one point between the questioning and the delivery of the sentence, he even grimly explains to the accused Kirk and McCoy that, according to Klingon law, "both sides present their cases at the same time," going on to comment that the defendants have had their turn, though none of this dialog is in the film. The script almost completely refers to the character as simply "defense attorney," with the name Colonel Worf used only in two instances of dialog as well as in a single scene description (the latter upon establishing his presence at Camp Khitomer). 
Colonel Worf was played by Michael Dorn, who also played the 24th century Starfleet officer Worf. Although it was never confirmed on screen, publicity materials for Star Trek VI indicated that Colonel Worf was intended to be the grandfather of his Next Generation namesake, and the father of Mogh. (Star Trek Encyclopedia 2nd ed., p. 563) Michael Dorn has confirmed that this was the filmmakers' intention.  Co-writer Denny Martin Flinn recalled, "The genesis was really Nick [Meyer] saying, 'How about if we get Michael Dorn to play the part of Worf? and everybody said 'Nick, The Next Generation is 75 years later!' and Nick said, 'Okay, we'll make it his grandfather' and that was it. Nick had not created the part of Worf for a particular actor, but we got Michael Dorn and they explained to him he couldn't play himself." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 143)
Michael Dorn remembered the offhand way he learned about his involvement in the project; "Nick Meyer was on set with Herman Zimmerman, the former production designer from our show and the movie. He just happened to walk by. We were introduced, and he said, 'I wrote a part for you on the show.' The story lent itself to Worf being there. They wanted to have a thread between the old and the new." (Cinefantastique, Vol. 22, No. 5, p. 52) Dorn further recalled, "Before we began shooting, I talked to the director and I asked, 'What do you want this guy to be? Do you want him to be like Worf or do you want him to be different?' And he said, 'No, we wanted him to be totally different. This is Worf's grandfather, so we want some flashes of Worf, but we don't want to see Worf 'cause you know we don't want it to be too close.'" (Star Trek: Communicator, issue #104, p. 63)
One element that Michael Dorn was not fond of was the prosthetics required for the role. He stated, "For the first time in my life, I was in makeup for almost 24 hours. That's a long time." (Star Trek: Communicator, issue #104, p. 63) He was, however, thrilled about the opportunity to play a role that essentially linked Star Trek: The Original Series with Star Trek: The Next Generation, describing the experience as "a lot of fun" and "an honor." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 143) He remarked, "It was wonderful." (Star Trek: The Magazine Volume 3, Issue 9, p. 19) However, he also said, "You don't think about it till it happens and then you realize how important it is." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 143) Early in his stint playing Colonel Worf, Michael Dorn enjoyed working with both Christopher Plummer and Rosana DeSoto. Having been a longtime fan of the original Star Trek series, he was also excited about meeting the cast of that show. He reminisced, "There was one day where they were shooting this huge scene and everybody was there, and I'm sitting in this little alcove in my chair, and right across from me are all of the characters–Shatner, Nimoy, everybody. On the outside I was really cool, but inside I'm thinking, 'Oh, my God, they're all there, and they are looking at me!' [....] That was one of the most special moments ever in this whole thing." (Star Trek: The Magazine Volume 3, Issue 9, p. 19)
On the differences between the two characters, Dorn noted, "I felt Worf was more at peace with himself in Star Trek VI than Worf on the television show, because he's a Klingon, all Klingon. He is a Klingon and he's from Klingon [sic], he's never been taken away from his family. He's spent all his time with Klingons and was more in touch with himself. He was more even-keeled and not quite as racked with inner turmoil." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 143)
The view that Colonel Worf is the grandfather of The Next Generation character of the same name is supported by novels such as The Art of the Impossible, which portrays a promoted General Worf as the father of Mogh. The book also establishes that the elder Worf was not a warrior of any type, saying that, as a defense attorney, his battlefield was the courtroom. Worf did, however, make sure that his son, Mogh, was a warrior. Worf, unlike many other Klingons during his time, did not hold a very high opinion of "The Great Curzon". The novel also states that Lorgh, the man who raises Kurn as his own son after the assault on Khitomer, was an old friend of Worf's, who also kept an eye on the younger Worf living in the Federation, to ensure that both the sons of Mogh would live to adulthood so that his friend's family line would continue.
In the novel The Forgotten War, the younger Worf mentions to one of the reptilian aliens called the Tarn – who are not the same as the Gorn – that he "had a grandsire" who was involved in a protracted battle against the Tarn, at a location called Garamora.
In the game Star Trek: Klingon Academy, it was revealed that Colonel Worf had a brother named Thok'Mak (Thok Mak at Memory Beta, the wiki for licensed Star Trek works), who was an instructor at the Elite Command Academy (Elite Command Academy at Memory Beta, the wiki for licensed Star Trek works).
In the second volume of the DC Comics Star Trek series, Colonel Worf appeared in an alternate timeline during the five-part "Time Crime" arc. In this reality, created by a Romulan plot, the Klingons had developed a peaceful society akin to the Federation, with whom they were staunch allies. Worf was a lieutenant aboard the USS Enterprise, under Kirk's command. Once the prime timeline was restored, Colonel Worf remained aware of his alternate self, due to the influence of the Guardian of Forever, which revealed that, in this reality, he was a defense attorney specializing in hard luck cases.
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