Sesame Street character debuts

The following is a list of known sources for when certain Sesame Street characters made their debut on the show.

Season 1

 * Big Bird - Debuted in the premiere episode.
 * Oscar the Grouch - Debuted in the very first episode.
 * Ernie and Bert - Appeared in the first episode, having previously appeared in the first test pilot.
 * Kermit the Frog - Appears in the first epsidoe, having already been around since Sam and Friends in 1955.
 * Cookie Monster - Appears in the first episode.
 * Grover - Appears in segments known to have debuited during the first season.
 * Professor Hastings - appears in segments known to have debuted in the first season.
 * Lefty the Salesman - Appears in segments known to have debuted in the first season.
 * Roosevelt Franklin and his mother - Appear in segments known to have premiered in the first season.
 * Little Bird - appears in segmnets known to have premiered during the first season.
 * Guy Smiley - Appears in segments known to have premiered in the first season.
 * Betty Lou - Appears in segments known to have premiered in the first season.

Season 2

 * Sherlock Hemlock - A Time Magazine marticle from 1970 mentions him as a new character in the second season. He made his debut in The second season premier.
 * Herbert Birdsfoot - A Time Magazine article from 1970 mentions him as a new character in the secodn season.

Season 3

 * Mr. Snuffleupagus - Big Bird first meets him in the third season premier. Songs From the Street and Sesame Street Unpaved also cite this as his debut season.

Season 4

 * Count von Count - Songs From the Street refers to this as The Count's debut season; He makes his debut in the season premier.
 * Sam the Robot - Sam meets Susan and Gorodn in the season premier.

Season 5

 * Biff and Sully - Songs From teh Street refers to this season as their first appearance.

Season 6

 * Rodeo Rosie - She meets the cast in the season premier.