Elmo is self-described as three-and-a-half years old and his birthday is on February 3. Elmo characteristically avoids pronouns in reference to himself, instead referring to himself in the third person (e.g. saying "Elmo wants this" instead of "I want this"). Sesame Street staff writer Nancy Sans once described Elmo's origins: "There was this extra red puppet lying around and the cast would pick him up sometimes and try to create a personality, but nothing seemed to materialize."
The puppet, originally known as "Baby Monster", was performed by Caroll Spinney and Jerry Nelson in the background of episodes from the early 1970s, Brian Muehl from 1979 to 1981, and Richard Hunt from 1981 to 1984. Sans continues that "...one day [in 1984], Kevin Clash, a talented puppeteer, raised him up and brought energy and life into Elmo and from that day forward we would all write for Elmo. Kevin's performance inspired the writers to develop Elmo's character". John Tartaglia, Matt Vogel, and Jim Martin have all been secondary performers for the character, providing movement for Elmo's arms and legs, particularly in green-screen shots.
Alongside Cookie Monster, Elmo has appeared in The Furchester Hotel, where he is taking an extended stay because of his fascination with the Furchester Hotel. His father Louie is the brother of Funella Furchester.
- He plays as SpongeBob SquarePants in ElmoBob MonsterPants (LegalizeAnytingMuppets Style)
- He plays as Dr. Cockroach in Sesame Street Muppets Vs Horror Characters (DaveGrrrrrrruly)