This article is from the ER FAQ, by Rose Cooper cooper@acm.cse.msu.edu with numerous contributions by others.
The following characters appear to be gone from the show
indefinitely.
[Especially the deceased ones.]
Dr. Anna Del Amico, played by Maria Bello
Pediatrician & ER resident (resigned)
[or, fell into the Void...]
Dr. David Morgenstern, played by William H. Macy
Former Chief of Emergency Services (resigned)
[...to go play with the sheep sheep sheep...]
Dr. Ellis West, played by Clancy Brown
Synergix Attending, and Kerry's ex-lover
[and, by sheer coincidence, Grown-up Baby Suzie...uh,
I mean, Lucy Knight, recently signed on? Hmmm...]
Dr. Angela Hicks, played by CCH Pounder
Surgical Attending
["doyled", season 4; "bobbed", season 5?]
Cynthia Hooper, played by Mariska Hargitay
Administrations Desk Clerk; was involved with Mark
Dr. William "Wild Willie" Swift, played by Michael Ironside
Former Chief of Emergency Services; Synergix Attending
Chris Law, played by Joe Torry
Accused Mark of killing his brother
Scotty Anspaugh, played by Trevor Morgan
Dr. Anspaugh's son and Jeanie's cancer patient (now deceased)
Walt, played by Ving Rhames
Jackie's husband/Peter's brother-in-law
["reincarnated as Baby Reese"]
Dr. Nina Pomerantz, played by Jami Gertz
Psychiatric consultant
["Outlived Her Usefulness"]
Dr. Dennis Gant, played by Omar Epps
Surgical intern, killed by train
Dr. Abby Keaton, played by Glenne Headly
Pediatric Attending surgeon, working in Pakistan now
Dr. Susan Lewis, played by Sherry Stringfield
ER Resident, fourth-year, moved to Phoenix
Dr. Greg Fischer, played by Harry J. Lennix
Infectious disease specialist; was involved with Jeanie
Bogdanalivetsky "Bob" ["bobbed"] Romansky, played by Malgoscha Gebel
Administrations Desk Clerk, former vascular surgeon in Poland
Mae Benton, played by Beah Richards
Peter Benton's mother, deceased
Reilly Brown, played by Scott Michael Campbell
EMT/Paramedic
Mrs. Cavanaugh (f.k.a. "Madame X"), played by Rosemary Clooney
A middle-aged woman and former torch singer with Alzheimer's
Deb Chen, played by Ming-Na Wen
Medical student doing rotations in ER
Claire, played by Channing Chase
Dr. Vucelich's assistant
Dr. Div Cvetic, played by John Terry
Psychiatrist, Susan's former boyfriend
Linda Farrell, played by Andrea Parker
Doug's girlfriend (mid-season 1), a pharmaceutical rep
Karen Hines, played by Marg Helgenberger
Doug's girlfriend (late season 2), and his father's boss
Hulda, played by Nicole Nagel
Flight attendant; occasional companion of Doug Ross
Iris, played by Joanna Gleason
Infomercial director who dated Mark Greene
Ivan, played by John LaMotta
Liquor store owner who kept coming in with gunshot wounds
Dr. Sara Langworthy, played by Tyra Ferrell
Surgical Resident
Diane Leeds, played by Lisa Zane
Doug's girlfriend (late season 1)
Jake Leeds, played by Zachary Browne
Diane's son
Chloe Lewis, played by Kathleen Wilholte
Susan's sister
Cookie Lewis, played by Valerie Perrine
Susan and Chloe's mother
Henry Lewis, played by Paul Dooley
Susan and Chloe's father
William Litman, played by Chris Edwards
Carol's pre-med physics classmate tutor
Liz, played by Liz Vassey
Young woman who had a brief physical relationship with
Carter
Raul Melendez, played by Carlos Gomez
Shep's paramedic partner, burned to death
Heather Morgan, played by Caitlin Dulany
Briefly dated Mark after being his patient
Sean O'Brien, played by Bradly Whitford
Widower who sued hospital and Mark for malpractice
Patrick, played by Kevin Michael Richardson
Mentally disabled young man who hung around ER
Timmy Rawlins, played by Glenn Plummer
Administration Desk Clerk
Rolando, played by Rolando Molina
Administration Desk Clerk
Ray Ross, played by James Farentino
Doug's father, killed in a car accident
Raymond "Shep" Shepherd, played by Ron Eldard
Paramedic, Carol's ex-boyfriend
Loretta Sweet, played by Mary Mara
Ex-prostitute, now secretary
Jimmy Sweet, played by Jake Lloyd
Loretta's son
Annie Sweet, played by Ashlee Lauren
Loretta's daughter
Dr. John Taglieri, played by Rick Rossovich
Staff Orthopedist, Carol's ex-fiancee'
Harper Tracy, played by Christine Elise
Medical student
Dr. Carl Vucelich, played by Ron Rifkin
Vascular surgeon
 
Continue to: