Though Uncle Fester is a regular on the TV series, Charles Addams' prototype for Fester in the New Yorker cartoons was almost exclusively solitary, never shown indoors with the other family (except once as a painted portrait), and only once outdoors with the children (going fishing with dynamite).
With the start of the TV series, The New Yorker magazine stopped running any Addams-Family-themed cartoons from Charles Addams until just prior to his death in 1988, although a few familiar characters were allowed solitary appearances (the prototypes for Pugsley, Cousin Itt, and Fester).
Cousin Itt is the only character whose name was carried over from the original New Yorker cartoons, where he was just "It".
Gomez was a lawyer.
Wednesday's pet, Homer, was a black widow spider. Her headless doll was named Marie Antoinette.
Pugsley's pet Octopus was named Aristotle.
Morticia's man-eating plant was named Cleopatra.
This show and its rival series, The Munsters, both debuted within a week of one another in September 1964. At the end of that year's TV season, The Munsters ranked #18 in the Nielsens, with a rating of 24.7, while this show came in at #23, with a 23.9 rating. At the time, Nielsens indicated what percentage of American TV households tuned in to any given program. By the end of the following year, both series were canceled.
It took Carolyn Jones two hours every day to put on Morticia's make-up. Topping it all off, she wore a wig made of human hair.
Cousin Itt's voice was done by producer Nat Perrin, who recited gibberish into a tape recorder and played it back at a higher speed.
Charles Addams never named his characters, but he had to come up with names for the characters on the TV show (it was one of the few contributions he made to the series). Within a week he decided on all of them - except for Mr. Addams, who almost wound up being called Repelli (for "repellent") instead of Gomez.
Thing, the disembodied hand/arm limb, was usually played by Ted Cassidy. When Lurch had to be on camera at the same time as Thing, however, associate producer Jack Voglin lent his hand. A third actor also played Thing on occasion, but his identity is not known.
Thing was usually a right hand. Ted Cassidy (Lurch) occasionally used his left hand just to see if anybody would notice. Thing also had an arm, which was seen when it reached outside for something while in its box.
The Addamses' version of a cuckoo clock was a wolverine that popped out and growled the hours of the day.
Gomez's favorite food was eye of newt.
The doorbell sound was a foghorn.
Wednesday Addams' name is a reference to the nursery rhyme that says, "Wednesday's child is full of woe."
Gomez and Morticia Addams were the first married couple on American TV implied to have a sex life.
John Astin was given the choice of two names for his character, and selected Gomez over Repelli. The son's name was originally to be Pubert, but was changed to Pugsley because Pubert sounded too sexual.
Carolyn Jones and John Astin decided to give Gomez and Morticia "a grand romance" as an antidote to the virtually asexual parents then common in television shows.
The train-crash sequence, in which the model trains collide and explode, was shot once, and that footage was used every time Gomez wrecked model trains.
Jackie Coogan was originally rejected as Uncle Fester. He went home, shaved his head, and did his own Fester makeup and costume. This won him the part.
The name of the Addamses' pet lion was "Kitty Cat".
Morticia's pet names for Gomez generally meaning "Darling"/"My Darling" are "Bubeleh" (Yiddish), "Mon Cherie" (French), Querido (Spanish). Gomez's pet names for Morticia also of the same affectionate meaning are "Cara Mia" (Italian), "Querida"/"Querida Mia" (Spanish), "Cara Bella" (Spanish literally for "beautiful face"; Italian for "beautiful darling").
Blucher (prounounced "Blooker") was the name of Gomez's stockbroker.
Morticia's maiden name was Frump.
Almost all episodes open in the Addamses' living room with the family playing and having fun. Activities included Gomez doing yoga headstands, flamenco dancing, sword fighting, bull whip practice, shooting thrown apples with crossbows and other bizarre games.
Whenever Gomez needs to know the time, he looks at both his wristwatch and his pocket watch. Each is hours different from the other but they always average to the correct time.
The Addamses often refer to the many cousins of their extended family. Cousins named are Blah, Bleak, Bleep, Blink, Blob, Cackle, Caliban, Clot, Creep, Crimp, Cringe, Curdle, Droop, Farouk, Fungus, Goop, Gripe, Grisly, Grope, Imar, Manuel, Melancholia, Nanook, Plato, Slimey, Slosh, Slump, Trivia, Turncoat, and Vague.