NBC wanted a handsome young actor to play Mark Gordon, but Michael Landon had a long history of refusing to work with better-looking actors. He was even behind Guy Williams's dismissal from Bonanza (1959), feeling threatened by the newcomer's good looks and charisma. Landon insisted that he would only star in the series if his friend and Little House on the Prairie (1974) co-star Victor French was cast. The character of Mark Gordon was rewritten to suit the middle-aged Victor French.
Michael Landon quit smoking in the summer of 1989 after Victor French died of lung cancer, although he continued to drink heavily.
This was Victor French's final television series. Some have speculated that Michael Landon decided to end the series after French died of lung cancer. In fact, it had already been agreed in June 1988 that the series would end because of falling ratings. Landon died in July 1991.
The show was initially a big success, and very important to a then-struggling NBC. By 1988, falling ratings led to the decision to cancel the series after the upcoming fifth season. Michael Landon suspected that if he shot a full 26-episode season, many of them would end up on the shelf unbroadcast, so he made a truncated season. Landon's suspicions were proven correct when NBC announced that instead of a regular time slot, the show would be used to fill last-minute and unexpected gaps in the schedule. The 13 episodes of season five were broadcast sporadically over the next year; the series finale, clearly intended for Christmas 1988, was broadcast in August 1989. Landon took his next project, Us (1991), to CBS, ending a 30-year relationship with NBC.
Viewers often assumed that Michael Landon was very religious, due to the Christian themes in his many series. According to Merlin Olsen, Landon never practiced any religion as an adult. His mother was an Irish Catholic, and his father was Jewish. In Michael Landon, the Father I Knew (1999), directed and written by Landon's son, Michael Landon Jr., Landon was portrayed as a serial adulterer with strained family relationships.