<Tr> <Th> First cousins </Th> <Td> <Ul> <Li> Miles Colby </Li> <Li> Monica Colby </Li> <Li> Bliss Colby </Li> </Ul> </Td> </Tr> <Ul> <Li> Miles Colby </Li> <Li> Monica Colby </Li> <Li> Bliss Colby </Li> </Ul> <P> Jeffrey Broderick "Jeff" Colby is a fictional character on the ABC prime time soap opera Dynasty, created by Richard and Esther Shapiro . Portrayed by John James, Jeff Colby was introduced in the show's first episode in 1981 and appeared as a series regular for six seasons until transferring to the spin - off companion series, The Colbys . The character returned to Dynasty upon the cancellation of The Colbys in 1987 and remained with the series until its final episode in 1989 . James later reprised his role for the 1991 miniseries, Dynasty: The Reunion . </P> <P> In the 2017 Dynasty reboot, Jeff is portrayed by actor Sam Adegoke . </P>

Who played jeff colby on the original dynasty