<Tr> <Th> Occupation </Th> <Td> Actor, voice actor </Td> </Tr> <Tr> <Th> Years active </Th> <Td> 1976--present </Td> </Tr> <P> Michael Dorn (born December 9, 1952) is an American actor and voice artist who is known for his role as the Klingon Worf in the Star Trek franchise . </P> <P> From his first appearance in the series premiere episode of Star Trek: The Next Generation, "Encounter at Farpoint", to his last in Star Trek: Nemesis, Dorn has appeared more times as a regular cast member than any other Star Trek actor in the franchise's history, spanning five films and 272 television episodes . He also appeared as Worf's ancestor, Colonel Worf, in the film Star Trek VI: The Undiscovered Country . </P>

Who played worf on star trek the next generation