Cousin Itt did not live in the mansion with the main characters, although he made frequent guest appearances when he would visit them. He was therefore a recurring character, not a main character. Although known to spend time in the chimney, Itt has his own room in the mansion, furnished in proportion to his size and with a low ceiling. He is depicted as a carefree bachelor with an extravagant lifestyle, and is renowned among the Addamses for his many female companions. He had an on-again/off-again relationship with Morticia's sister Ophelia.
Itt Addams is the cousin of Gomez Addams. He is a short being whose entire body is completely covered with hair. He usually wears sunglasses, a derby hat, and gloves. He speaks in a high-pitched gibberish language which the other members of the family can understand though it is incomprehensible to anyone else. The Addams find nothing odd about Itt's appearance, and in one episode of the series, Gomez is surprised by the idea that other people could not understand Itt's speech. Itt is often celebrated by the family as being "full of talent" in areas such as acting, singing, and marriage counseling. He is also known to have an extremely high IQ of over 300 (as explained by Gomez), shown when he guesses every Rorschach Test correctly, places all of the boxes in the correct slots, and in other ways In one episode, Cousin Itt took elocution lessons and developed a (dubbed) voice with a mellifluous, mid-Atlantic accent; this voice did not survive into future episodes.