History Trivia / ER

** Carol's mother Helen was played by Georgiana Tarjan in Season 1 and then by Rose Gregorio in Seasons 3-5.

* HilariousInHindsight: One of the very first roles of Creator/GeorgeClooney was in a short-lived sitcom called ''[=E/R=]'', where he played the supporting role of "Ace", a snarky ER technician. A decade later, he gained world-wide fame thanks to playing Doug Ross. Oh, and both series are set in Chicago.

* TheRedStapler: Applications to ER medical residency programs skyrocketed after the series premiered. TropesAreNotBad, since ER residency is a good start for medical career.

* TheRedStapler: Applications to ER medical residency programs skyrocketed after the series premiered.

** For Creator/GeorgeClooney.

* {{Blooper}}:
** In "Love's Labor Lost", as Mark futilely tries to revive the patient, Carol can clearly be seen taking off her glasses in the background. When the patient is pronounced dead and we get the individual reactions of everyone in the room (Susan, Carol, Lydia, Carter and Jing-Mei), Carol is seen taking off the glasses again.
** During a surgery scene in Season 3, Abby Keaton charges into the OR walking forward, pushing the door open with her hands. No surgeon would ''ever'' enter an OR like this--it would contaminate their hands.

* NamesTheSame: [[Literature/JohnCarterOfMars John Carter]], huh.

* McLeaned: Lucy Knight was murdered by a schizophrenic patient in Season 6 when Creator/KellieMartin wanted to leave the show. In [[https://web.archive.org/web/20170906204755/https://www.vox.com/2017/9/6/16257986/er-lucy-death-kellie-martin this 2017 Vox interview]], Martin explained that she felt working on a medical drama only one week after losing her younger sister to lupus hit too close to home throughout her short-lived tenure on the show, and was relieved when she learned Lucy was being killed off.

** Wyle's attitude apparently also affected other co-stars--he has admitted to being hostile to other newcomers such as Creator/ErikPalladino and Creator/MichaelMichele. Reportedly, when Wyle once complained about the buffet for cast and crew, Creator/GoranVisnjic (Luka Kovac) snapped "How dare you complain about this food when there are people all over the world who would give their lives for a fraction of what you have!" (Apparently this was due to the Croatian Visnjic's experiences as a veteran of the UsefulNotes/TheYugoslavWars.)

* RecycledScript: Luka's downward spiral in Season 9 is very reminiscent of Doug's in Season 5, right down to a rehash of "Last Call"--Luka getting into a car accident and seriously injuring his female passenger.

** Paul Adelstein played a patient's father in Season 6 and then a patient's husband in Season 8.

** It began to feel like the actors were nominated based on where their names fell in the credits. Creator/NoahWyle was a co-lead by Season 3, but he still fell into the Supporting Actor category. Starting with Season 3, Creator/JuliannaMargulies was properly moved up to Lead Actress, but Creator/LauraInnes, who was easily as prominent from Seasons 4-9, never made it out of the Supporting Actress category.

** Maggie Doyle offhandedly mentions that she's a vegetarian--"No meat, no men." So is her actress, Jorja Fox.
** Both Michael Michele and Creator/ThandiweNewton and their respective characters, Cleo and Kem, are biracial, though the mixes are different--Michael and Thandiwe's fathers are white, while Cleo and Kem's mothers are.

** Creator/NoahWyle (John Carter) and Creator/KellieMartin (Lucy Knight) did not get along, resulting in her character not being used very much or developed once he nixed plans for her to be his girlfriend[[note]]To be fair, he also [[JerkassHasAPoint truthfully pointed out]] that such a relationship would be inappropriate (she was a third-year medical student while he was a second-year resident, therefore she was his subordinate) and out of character for Carter[[/note]].
** Wyle's attitude apparently also affected other co-stars--he has admitted to being hostile to other newcomers such as Erik Palladino and Michael Michele. Reportedly, when Wyle once complained about the buffet for cast and crew, Creator/GoranVisnjic (Luka Kovac) snapped "How dare you complain about this food when there are people all over the world who would give their lives for a fraction of what you have!" (Apparently this was due to the Croatian Visnjic's experiences as a veteran of the UsefulNotes/TheYugoslavWars.)

** Maggie Doyle offhandedly mentions that she's a vegetarian--"No meat, no men". Her actress, Jorja Fox, is one as well, as was her character in ''Series/{{CSI}}'', Sara Sidle.

** David Brisbin, who plays Alexander Babcock, is married to Creator/LauraInnes. They got to interact at least once, when Kerry is in the ICU screaming at Doug for doing a procedure in secret and without parental consent.

** Four actors from ''Series/LifeGoesOn''--Creator/KellieMartin (Becca/Lucy Knight), Troy Evans (Artie/Frank Martin), Creator/ChadLowe (Jesse/George Henry), and Chris Burke (Corky/George)--appeared on the show at various times, though never together.

** A number of actors initially cast in recurring roles were offered or considered being upped to regular status but either declined the offer or didn't end up working out. These include Michael Ironside, Ron Eldard, Jorja Fox, Creator/CCHPounder, Creator/BusyPhilipps and Glenn Howerton, among others.

** Vondie Curtis-Hall played Carter's suicidal transgender patient, Rena Carlton, in Season 1 and then Roger [=McGrath=] in Season 8.

** Both Michael Michele and Creator/ThandieNewton and their respective characters, Cleo and Kem, are biracial, though the mixes are different--Michael and Thandie's fathers are white, while Cleo and Kem's mothers are.
** Neela mentions playing the viola in "Damaged" and "Alone in a Crowd", and she plays to her visiting parents in a deleted scene from the former. Parminder Nagra does actually play the viola.
** Ray is originally from Baton Rouge, and he spends Seasons 11 and 12 as a rock musician. Shane West is actually from Baton Rouge, and he's also a punk rock musician.
** Goran Visnjic and his character Luka Kovac not only both hail from Croatia, they had traumatic experiences in UsefulNotes/TheYugoslavWars. Though Luka's experiences were as a doctor, not a combatant, and far worse than Goran's--losing his entire family.

** Possibly to avoid canceling each other out (as possibly happened to Anthony Edwards and Creator/GeorgeClooney along with Creator/NoahWyle and Eriq La Salle), Julianna Marguiles was nominated for Best ''Supporting'' Actress during the time when Sherry Stringfield, who was nominated for Lead, was a cast member, even though the two had roughly the same amount of screen time and storylines.
** It began to feel like the actors were nominated based on where their names fell in the credits. Arguably Noah Wyle was a co-lead by Season 3, but he still fell into the Supporting category. Starting with Season 3, Julianna Margulies was (properly) moved up to Lead but Laura Innes, who was easily as prominent from Season 4 to Season 9, never made it out of the Supporting category.

** Yvette Freeman would get to sing about OnceASeason, often in the ChristmasEpisode. As she has a lovely voice, nobody's complaining.
** In the last few seasons, the torch passed to Scott Grimes.

** Creator/JuliannaMargulies originally read for the part of Mark's first wife Jen.

** In 1995, Rachel Greene celebrates her 6th birthday. Assuming a birth year of 1989, by 2001 Rachel would have been 12. Creator/YvonneZima, who had played Rachel up to this point and who was exactly 12, was replaced by 14-year-old Creator/HalleeHirsh.

* DirectedByCastMember: Several main or recurring cast members helmed episodes of the show. These included Anthony Edwards, Paul [=McCrane=], Laura Innes, Eriq La Salle, and Vondie Curtis-Hall. For a few of them, they continued to direct after their characters left the show.
* DisabledCharacterDisabledActor: Creator/MatthewWatkins, who plays Reese, is deaf in RealLife.

* FakeAmerican: Gloria Reuben (Jeanie) is Canadian.
* FakeMixedRace: Inverted. Gloria Reuben is of mixed race (black mother, biracial father). Jeanie is apparently not--we never learn much about her background, but she never mentions either parent being white.
* FocusGroupEnding: More like a focus group ''beginning''. The pilot episode was to feature Nurse Carol Hathaway committing suicide via a drug overdose. However, test audiences liked her character and were intrigued by the relationship hinted at between her and Dr. Doug Ross. As a result, Carol miraculously recovered and became one of the show's best known heroines.

** Parminder Nagra (Neela) was pregnant towards the end of the final season. There were attempts to disguise her bump by filming her scenes from the chest up, having her sit, wearing surgical scrubs, keeping her coat on, using her bag to cover up, or placing her behind counters or gurneys, but it was still visible in wide shots.
** Subverted with Creator/MingNaWen (Jing-Mei Chen) and Creator/AlexKingston (Elizabeth Corday). Although their pregnancies were written in, the actresses were much further along than their characters, resulting in this trope for several months until they could catch up.

** Creator/NoahWyle (John Carter) and Creator/KellieMartin (Lucy Knight) did not get along, resulting in her character not being used very much or developed (once he nixed plans for her to be his girlfriend)[[note]]To be fair, he also [[JerkassHasAPoint truthfully pointed out]] that such a relationship would be inappropriate (she was a third-year medical student while he was a second-year resident, therefore she was his subordinate) and out of character for Carter[[/note]].

* InMemoriam: When creator Creator/MichaelCrichton passed away in 2008, Eriq La Salle gave out a speech about Crichton's passing.
* McLeaned: Lucy Knight was murdered by a schizophrenic patient in Season 6 when her actress Kellie Martin wanted to leave the show. In [[https://web.archive.org/web/20170906204755/https://www.vox.com/2017/9/6/16257986/er-lucy-death-kellie-martin this 2017 Vox interview]], Martin explained that she felt working on a medical drama only one week after losing her younger sister to lupus hit too close to home throughout her short-lived tenure on the show, and was relieved when she learned Lucy was being killed off.

** Perhaps most notably, Mark's eldest daughter Rachel Greene was originally played by Yvonne Zima in Seasons 1-6 and then by Hallee Hirsh for the rest of the series.

** Rather egregiously, Roger [=McGrath=] (Carla's husband) was played by Victor Williams in Seasons 4-7, but in Season 8 he was suddenly played by ''Series/ChicagoHope'''s Vondie Curtis-Hall, who previously guest-starred as Carter's suicidal transgender patient in Season 1.

** Benton's brief, troubled relationship with Elizabeth is partly because Benton can't get over his discomfort with [[WhereDaWhiteWomenAt dating a white woman]], echoing his portrayer's sentiments--Eriq La Salle believed that having Benton date a white woman [[UnfortunateImplications played into dubious ideas]] about successful black men being "above" dating black women.
** Julianna Marguiles admitted in an interview that she and George Clooney had a "huge crush" on each other throughout their time on the show. To this day, they remain very good friends and even call each other "Doug" and "Carol".
** Anthony Edwards and Mare Winningham had been friends for years before she had an arc as the loopy and fake Dr. Amanda Lee. 23 years later, the two married.

** David Brisbin, who plays Alexander Babcock, is married to Laura Innes. They got to interact at least once, when Kerry is in the ICU screaming at Doug for doing a procedure in secret and without parental consent.

* RecycledScript: Luka's downward spiral in Season 9 is very reminiscent of Doug's, right down to a rehash of "Last Call"--Luka getting into a car accident and seriously injuring his female passenger.

** Also counts to a lesser extent for Julianna Marguiles, Creator/NoahWyle, and Mekhi Phifer.
** This was true for most of the original main cast, subsequent main cast, and supporting cast, although none of them have reached the heights Clooney has. Anthony Edwards is the exception--he was already well-known before the show, appearing in major roles in ''Film/RevengeOfTheNerds'' and ''Film/TopGun'', and he was the de-facto star of the show for the first eight seasons.

** Three actors from ''Film/TopGun''--Anthony Edwards (Goose/Dr. Mark Greene), Rick Rossovich (Slider/Tag), and Michael Ironside (Jester/Dr. William "Wild Willie" Swift)--appeared on the show.
** Four actors from ''Series/LifeGoesOn''--Kellie Martin (Becca/Lucy Knight), Troy Evans (Artie/Frank), Chad Lowe (Jesse/George Henry), and Chris Burke (Corky/George)--appeared on the show at various times, though never together.
* WagTheDirector: According to some reports, the romantic relationship between Dr. Benton (played by the African-American Eriq La Salle) and Dr. Corday (played by the white Creator/AlexKingston) ended because La Salle thought that it had UnfortunateImplications suggesting that successful middle-class black people were "above" dating other black people.

** Carol was originally slated to die in the pilot, committing suicide after her break up with Doug. Julianna Margulies' performance in the pilot convinced the show-runners to have her recover and make her a regular in the subsequent episode.

** The producers wanted to pair Carter and Lucy, but Creator/NoahWyle was adamantly opposed to this, feeling that it would be out of character for Carter to pursue an inappropriate relationship--Lucy was still a medical student and therefore Carter's subordinate.

** Noah Wyle was originally supposed to appear in a handful of episodes in Season 13, but this was pushed back to Season 14 (which was supposed to be the final one). However, the 2007-2008 Writers' Strike led to NBC renewing ''ER'' once again, so he ended up appearing again in Season 15 ([[BackForTheFinale along with several other cast members]]).
** A number of actors initially cast in recurring roles were offered or considered being upped to regular status but either declined the offer or didn't end up working out. These include Michael Ironside, Ron Eldard, Jorja Fox, CCH Pounder, Busy Phillips and Glenn Howerton, among others.

** The RealLife pregnancies of several of the show's actresses--Creator/MingNaWen, Creator/AlexKingston, and Sherry Stringfield--resulted in their characters being pregnant as well.
** The injuries that Doug sustained while rescuing Ben in "Hell & High Water" are real cuts that Creator/GeorgeClooney received while filming the scenes.
** Clooney also sprained his ankle prior to filming the Season 3 episode "Whose Appy Now?" Ergo, so did his character Doug. This also resulted in a hilarious IronyAsSheIsCast moment when he and Kerry are limping down the hall in tandem and she snaps at him before he explains his predicament. ''Her'' limp is the fake one, as Laura Innes is not disabled in RealLife.

** Shiri Appleby played a patient in the {{Pilot}} and then Dr. Daria Wade in the final season.

** Vondie Curtis-Hall played Carter's suicidal transgender patient in Season 1 and then Roger [=McGrath=] in Season 8.

** Anthony Edwards and Mare Winning ham had been friends for years before she had an arc as the loopy and fake Dr. Amanda Lee. 23 years later, the two married.

* AwardCategoryFraud: Possibly to avoid canceling each other out (as possibly happened to Anthony Edwards and Creator/GeorgeClooney along with Creator/NoahWyle and Eriq La Salle), Julianna Marguiles was nominated for Best ''Supporting'' Actress during the time when Sherry Stringfield, who was nominated for Lead, was a cast member, even though the two had roughly the same amount of screen time and storylines.

* TheDanza: In the Season 6 episode "Humpty Dumpty", Rosalind Chao plays a neurologist named Doctor Chao.

** Jesse Borrego played an HIV positive patient in the Season 4 premiere and then desk clerk Javier in Season 14.

** Diane Delano played an abused girlfriend in Season 3 and then a hypochondriac patient in Season 9.

** In 1995, Rachel Greene celebrates her 6th birthday. Assuming a birth year of 1989, by 2001 Rachel would have been 12. Creator/YvonneZima, who had played Rachel up to this point and who was exactly 12, was replaced by 14-year-old Creator/HalleeHirsh.
** In Season 7, Carter is relentlessly teased for dating Rena Trujillo, a 19-year-old Pediatric intern. Her actress, Creator/LourdesBenedicto, was actually 26 at the time, and is only three years younger than Creator/NoahWyle.