This is the only prime time series ever to run in consecutive seasons on three major televisions networks: on CBS from 1957 to 1959, on NBC from 1959 to 1961 and on ABC from 1961 to 1962.
Although she never sings in the series, Noreen Corcoran (Kelly) released several pop singles during the early 1960s. One charted briefly. Corcoran was also a talented dancer who had trained in several forms of dance from the age of 3, yet doesn't dance during the program's run.
In an interview, John Forsythe revealed that they had originally decided on another young actress, Helen Green, to play his niece Kelly. But as they finished watching the auditions, Forsythe's friend, Ronald Reagan, was sitting in the back of the theater, and he told them they were making a mistake and were hiring the wrong girl. He told them they needed a more down-to-earth girl for the part, "someone who looks like a niece, not Hollywood's idea of a niece". At first, they told Reagan that the idea was ridiculous, but as they walked back to the office, they came to the realization that he had a point, that Noreen Corcoran "was everybody's daughter". So they looked at the film again, concluded that Reagan was absolutely right, and gave Noreen Corcoran the part.
Despite his character's accent on the show, Sammee Tong (who played Peter, the Chinese houseboy) was actually born in the United States, and graduated from Stanford University.