The original cast consisted of nine star-billed actors: Ellen Pompeo, Sandra Oh, Katherine Heigl, Justin Chambers, T. R. Knight, Chandra Wilson, James Pickens Jr., Isaiah Washington, and Patrick Dempsey.

During her time as an intern, Grey works alongside fellow physicians Cristina Yang (Sandra Oh), Izzie Stevens (Katherine Heigl), Alex Karev (Justin Chambers) and George O'Malley (T. R. Knight), who each struggle to balance their personal lives with hectic schedules and stressful residency requirements.

The penultimate episode of Season 3 introduces Lexie Grey, Meredith's half-sister who unexpectedly decides to pursue her internship at Seattle Grace Hospital after her mother's sudden death, and begins an on-again, off-again relationship with Sloan.

[26] Burke and Yang, having been engaged,[27] endeavor to plan their wedding, while Montgomery departs the show in the Season 3 finale, relocating to California, seeking a new life, thus becoming the lead character of the spin-off Private Practice.

[50] However, all plans are put on hold when several doctors from Seattle Grace Mercy West Hospital are engaged in a plane crash, which kills Lexie and endangers Meredith, Shepherd, Yang, Sloan and Robbins in the Season 8 finale.

The fourteenth season also saw the introduction of Tom Koracick who worked as a new neurosurgeon alongside Amelia Shepherd, Levi Schmitt who is a new intern at the hospital, as well as Andrew's sister, Carina DeLuca, an obstetrician who enters into a relationship with Robbins.

[17] In the first season, Olivia Harper (Sarah Utterback), a nurse who appeared on the show occasionally until getting laid off in the merger with Mercy West,[42] engages in a sexual relationship with O'Malley, giving him syphilis.

[41] While Bailey takes a sabbatical, due to her pregnancy, the cheerful Dr. Sydney Heron (Kali Rocha), fills her position as the resident supervising Grey, Yang, Stevens, Karev and O'Malley,[57] and makes occasional appearances until the fifth season.

[65] Facing death, Stevens cuts Duquette's left ventricular assist device (LVAD), to elevate his position on the United Network for Organ Sharing (UNOS) transplant list.

[77] Following the announcement of her relationship with Robbins (Jessica Capshaw), Callie's father Carlos Torres (Hector Elizondo) initially contests his daughter's concurrence in homosexuality,[80] but eventually accepts it,[43] and he reappears several times throughout the series.

[c][89] Conceived as a patient with a tumor condition who later develops diabetes, Henry Burton (Scott Foley) befriends Dr. Altman and eventually joins her in marriage only to get treated using her medical insurance,[90] until he dies while undergoing heart surgery in season 8.

In the season 9 premiere, interns Dr. Jo Wilson (Camilla Luddington), Dr. Shane Ross (Gaius Charles), Dr. Stephanie Edwards (Jerrika Hinton), Dr. Leah Murphy (Tessa Ferrer) and Dr. Heather Brooks (Tina Majorino) are introduced.

[100] Lauren Boswell (Hilarie Burton) is introduced as a craniofacial surgeon consulting on a case at Grey Sloan Memorial[101][102] who showed romantic interest in Arizona and eventually ended up having a one-night stand with her.

[106][107] The conclusion of season 10 has Cristina leaving Grey Sloan for Dr. Burke's job as head of Klausman Institute for Medical Research in Zurich, while Dr. Ross makes a last-minute decision to follow her in order to study under her.

[114] ABC Entertainment President, Steve McPherson, explained the scheduling change: "Ultimately, we decided that, without having adequate lead time or marketing dollars to devote to moving either show so late in the season, we'd continue to let [Grey's Anatomy] build on its tremendous momentum through May.

[126] Other key members of the writing staff include Vernoff, Wilding, Peter Nowalk, Stacy McKee, William Harper, Zoanne Clack, Tony Phelan, Joan Rater, and Debora Cahn.

[168][169] In March 2014, it was announced that Isaiah Washington, who portrayed Preston Burke in the first three seasons of the show, would make a guest appearance to coincide with the departure of series regular Sandra Oh, his former on-screen love-interest.

Notably, air ambulances land on the KOMO-TV news copter's helipad, suggesting the hospital's proximity to the Space Needle (located across the street from Fisher Plaza), the Seattle Monorail, and other iconic landmarks.

[206] At the beginning of season 4, the show aired its final special entitled "Come Rain Or Shine", created to transition viewers from Grey's Anatomy to Private Practice, which was narrated by the editors of People magazine.

"[297] Shortly after its initial airing, the Chicago Tribune's Maureen Ryan called Grey's Anatomy the new Friends (a concluded National Broadcasting Company (NBC) sitcom following the lives of a group of young adults, that for all of its 10-year run was in the top-5 for viewer ratings).

[298] It further garnered positive reviews: Christopher Monfette of IGN added "The second season of this medical drama expertly wove its signature elements of complex relationships, whimsical banter and challenging life-lessons; all to a montage-fetish, indie-rock soundtrack.

Alex Keen of The Trades wrote that Lexie's "presence and confidence have increased quite a bit ... and actress, Chyler Leigh, does a fantastic job of making this progression feel seamless.

"[320] Contrasting with Carter's view, Monfette of IGN said that it speedily found itself "mired in the annoying and absurd", adding: "This third season may very well represent a case of over-writing a concept that has, perhaps tragically, run bone-dry on narrative fuel.

[348] Media analyst Steve Sternberg of Magna Global USA explained the show's broad appeal, noting that "roughly 80 percent of households during prime time only have one TV set on.

[365] In 2016, a New York Times study of the 50 TV shows with the most Facebook Likes found that Grey's Anatomy was "most popular in a swath of the middle of the country, particularly in areas with a lower percentage of college graduates".

On February 21, 2007, The Wall Street Journal reported that ABC was pursuing a spin-off medical drama television series for Grey's Anatomy featuring Walsh's character, Addison Montgomery.

[452] The backdoor pilot that aired on May 3, 2007, sees Montgomery take a leave of absence from Seattle Grace Hospital, to visit her best-friend from Los Angeles, Naomi Bennett (Merrin Dungey, later Audra McDonald), a reproductive endocrinology and infertility specialist.

[457] The drama was titled Private Practice, and its premiere episode followed the second part of the season debut of Dancing with the Stars, and provided a lead-in to fellow freshman series Dirty Sexy Money.

Grey's Anatomy: B-Team stars Sophia Taylor Ali (Dahlia Qadri), Jake Borelli (Levi Schmitt), Alex Blue Davis (Casey Parker), Jaicy Elliot (Taryn Helm), Rushi Kota (Vik Roy) and Jeanine Mason (Samantha "Sam" Bello) with special guest appearances made by Justin Chambers (Alex Karev), Kelly McCreary (Maggie Pierce), Kevin McKidd (Owen Hunt) and James Pickens Jr. (Richard Webber).

For the first 2 seasons, the show's main title theme was an excerpt from "Cosy in the Rocket", by British duo Psapp; it is featured on the first soundtrack album released via ABC's corporate cousin, Hollywood Records, on September 27, 2005.