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. In The CW's 2017 Dynasty reboot, Jeff is portrayed by Sam Adegoke. In this series, Jeff is the brother of Monica Colby (Wakeema Hollis) and the son of Cesil Colby (Hakeem Kae-Kazim) and Dominique Deveraux (Michael Michele), who is the half-sister of Blake Carrington (Grant Show).