J.D.
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Finale: Part 1 and 2” (Season 8, Episodes 18 and 19)
Christopher Turk
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Finale: Part 1 and 2” (Season 8, Episodes 18 and 19)
Carla Espinosa
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Finale: Part 1 and 2” (Season 8, Episodes 18 and 19)
Elliot Reid
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Finale: Part 1 and 2” (Season 8, Episodes 18 and 19)
Dr. Cox
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Finale: Part 1 and 2” (Season 8, Episodes 18 and 19)
Bob Kelso
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Finale: Part 1” (Season 8, Episode 18)
The Janitor
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Finale: Part 1 and 2” (Season 8, Episodes 18 and 19)
Laverne Roberts
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Long Goodbye” (Season 6, Episode 15. Although she did appear in "My Finale" during J.D.'s fantasy scene.)
Ted Buckland
First appearance: “My First Day” (Season 1, Episode 1)
Last appearance: “My Finale: Part 2” (Season 8, Episode 19)
Jordan Sullivan
First appearance: “My Bad” (Season 1, Episode 6)
Last appearance: “My Finale: Part 1” (Season 8, Episode 18)
Rowdy
First appearance: "My Mentor" (Season 1 Episode 2)
Last appearance: "My Last Words" (Season 8, Episode 2)