the role was originated by two unknown infant actors on the december 11, 1981 episode. the unknown child actors were replaced by eric farlow in 1982, when the character made an appearance on the series spin-off, "knots landing". farlow first appeared in the episode, "new beginnings" which first aired on october 29, 1982. farlow last appeared on the "dallas" episode, "swan song" which aired on may 17, 1985. joshua harris then stepped into the role on september 27, 1985, in the episode "the family ewing." harris last appeared in the penultimate episode "the decline and fall of the ewing empire" which aired on april 26, 1991. chris demetral stepped into the role of christopher in 1996 for the television film, "".