Three of the first season episodes were credited with pen names: "The Walls of Jericho", Forrest van Buren; "The Good Samaritan", Sylvia Clayton; and "Epiphany", Sylvia van Buren. The names were taken from the two main characters of the film, Clayton Forrester and Sylvia van Buren.
In her room at the Whitewood Sanitarium, Sylvia van Buren has a picture of Dr. Clayton Forrester by her bed.
All the episode titles in the first season are Biblical references.
Originally, the Morthren deity, the Eternal, was to be called the Immortal (presumably to tie in with the "To Life Immortal" exchange of the Mor-Tax in the first season) and was going to speak in English.
This series was conceived as a sequel to the original 1950s classic movie. In several episodes, the character of Sylvia Van Buren appears, played by the original actress, and in one episode several characters go back through time to the time of the original movie.
At the beginning of the first airing of the first episode there was a brief sequence of clips from the 1953 movie with narration over it. The very last shot is a black and white image of a small boy standing in the wrecked Los Angeles from the end of the movie: the young Harrison Blackwood. This sequence was never shown again.
Originally, Paramount had conceived the series not as a sequel or for television, but as a film remake of the _The War of the Worlds (1953)_ with George A. Romero slated to direct.
The old war machine that rises at the Indian Reservation is a tripod. This is in reference to the way in which the Martian war machines are described in the H.G. Wells novel.
A total of nine actors played the members of the triumvirate Advocacy in the first season. Not only was Ilse von Glatz the only woman to play an Advocate, but she assumed the role the longest appearing in all but two episodes. However, when the Advocacy were set to be killed off in the first Season 2 episode "The Second Wave", the triad was played by uncredited actors.
The voice of The Eternal when conferring with the Advocats is actually recordings of deep sea whale songs.
In its second season, this series underwent a dramatic format change. The show title was changed to "War of the Worlds: The Second Invasion." The present-day setting of the first season was changed to a post-apocalyptic future where the US is undergoing a second Great Depression, several main characters were killed during the pilot of the second season and the alien fighting team were cut off from government support. The aliens could now produce clones of humans which they could control and the plot point that required aliens to "change bodies" every 24 hours was removed. This last change allowed actors playing alien characters to become regular and recurring cast members.