Originally, the show was intended as a starring vehicle for Victoria Principal, due to the fact that Pam would act as a buffer between the Ewings and the Barneses. J.R. was intended to be more of a supporting character. However, the producers were so impressed by Larry Hagman's portrayal of the immoral J.R., that he soon became the show's main character. Victoria stayed the hero though, and pretty soon it become angel Pam vs. Devil JR.
The house used as the "Southfork Ranch" house was a real Texas residence called "Duncan Acres", owned by Joe R. Duncan (or J.R. Duncan). When the show became popular, tourists from all over the world visited the house day and night. The Duncan family was forced to sell the house, and it is now a museum devoted to the show.
In several of the early episodes of the series, Lucy (Charlene Tilton) and Ray (Steve Kanaly) were often portrayed as lovers. However, when it was revealed that Ray was Jock's illegitimate son, and therefore Lucy's uncle, his affair with Lucy was never mentioned again.
Larry Hagman (J.R. Ewing), Patrick Duffy (Bobby Ewing), Ken Kercheval (Cliff Barnes), Linda Gray (Sue Ellen Ewing) and Steve Kanaly (Ray Krebbs) are the only actors to appear in both the first and last episodes of the series: Digger's Daughter (1978) and Conundrum, Part 1 and 2 (1991).
In the mid 1980s, Linda Gray was briefly fired from this show after asking for a pay raise, and requesting that she be given a chance to direct episodes like Larry Hagman and Patrick Duffy. However, Hagman threatened to leave the show because he didn't feel they could have J.R. without Sue Ellen.