Characterized by Rhimes as a "dork" with issues expressing her feelings, Lexie transfers to the fictional Seattle Grace Hospital as a surgical intern following the sudden death of her mother, Susan Grey (Mare Winningham).

Her main storylines throughout the series focus on her struggles with the pressures of a highly competitive profession, her initially strained relationship with Meredith, and her on-again, off-again romance with plastic surgery attending Mark Sloan (Eric Dane).

Despite their differences in upbringing, the Grey sisters ultimately form a strong familial bond after Lexie moves into Meredith's house.

[11] She demonstrates a strong aptitude for both plastics and neurosurgery, and is considered one of the most talented young surgeons of her cohort, often being asked to assist on many high-profile surgeries.

However, following her mother's sudden death due to complications from the hiccups, Lexie decides to move back to Seattle to care for her grieving father.

She seeks the help of Callie Torres (Sara Ramirez) and Owen Hunt (Kevin McKidd) to treat him, and Sadie takes the blame to spare Lexie further embarrassment.

[41] When Lexie is chosen by Mark to assist with a rare facial transplant surgery, her peers mock her, suggesting she's only involved due to their relationship.

[48] The residents face growing stress in the wake of Chief Webber's announcement that Seattle Grace will undergo an administrative merger with Mercy West Hospital, resulting in potential layoffs.

[49] Following the merger, Lexie clashes with Mercy West resident April Kepner (Sarah Drew), who attempts to undermine her.

[50] When a patient dies due to medical negligence, Webber starts witch hunt to trace back the culprit and identify the cause of death.

[53][54] A heartbroken and intoxicated Lexie has a one-night stand with Alex , but feels guilty and confesses to Mark, who is furious despite admitting to a similar encounter with Addison Montgomery (Kate Walsh).

[59] In her search for medical supplies, Lexie comes face-to-face with Gary Clark, but she manages to escape when a SWAT team member wounds him.

[59] After openly acknowledging the shooting as a mass murder during a therapy session with trauma counselor Andrew Perkins (James Tupper) and the other residents, Lexie experiences a psychotic breakdown stemming from PTSD and sleep deprivation while treating a patient.

After recovering and being cleared for surgery, Lexie confronts Alex at Cristina and Owen's wedding, reminding him that she saved his life during the hospital shooting, effectively knocking him down a peg.

[62] As her confidence returns, she helps Miranda Bailey (Chandra Wilson) discover a cure for hospital fistula, further solidifying her status as a competent surgeon.

Lexie confides in Jackson that she is frustrated with the people in her life, especially Mark and her father, making life-changing decisions without considering her feelings.

[75] Although initially content in her relationship with Jackson, Lexie becomes increasingly distraught when she discovers that Mark has started dating an ophthalmologist named Julia Canner (Holley Fain).

Although the surgery is initially celebrated as a success, the patient suffers severe brain damage, losing their ability to speak, leaving Lexie devastated.

Shortly after, Lexie is assigned to a team of surgeons headed to Boise, Idaho to separate conjoined twins, along with Mark, Meredith, Derek, Cristina, and Arizona Robbins (Jessica Capshaw).

While Cristina searches for supplies, Mark stays by Lexie's side, holding her hand and professing his love, envisioning a future together with marriage and children, believing they are "meant to be".

Mark is soon placed on life support due to the extensive internal injuries he sustained during the plane crash and, as determined by his will, the machines keeping him alive are turned off as he shows no signs of waking after 30 days.

When the remaining survivors of the plane crash pool their compensation money to purchase Seattle Grace Mercy West, they agree to rename it "Grey Sloan Memorial Hospital" in tribute to Lexie and Mark.

In season 15, Lexie's spirit appears alongside the ghosts of Mark, Derek, George, Doc and Ellis as they watch Meredith leave the hospital after treating a patient whose family celebrates the Day of the Dead.

Following Isaiah Washington's departure, who portrayed Preston Burke, it was reported that the show's executives were planning on adding new cast members, including Lexie.

[97][98] On casting Leigh as Lexie, Grey's Anatomy creator Shonda Rhimes said: "We met with a lot of young actresses, but Chyler stood out—she had a quality that felt right and real to me.

"[103] Following the death of her character, Leigh released a statement saying:Earlier this year, I made the decision that season eight would be my last on Grey's Anatomy.

Regarding her character, Leigh commented: "She's a very vulnerable person from a very healthy background—she knows how to make good relationships, but at this point [Season 4], she's coming into so much opposition she's trying to adjust to it.

She decided that she could live with being Alex's plaything, no strings attached, but when push came to shove, and [Karev's ex-girlfriend] came back for a booty call or two, she showed her true Grey colors and couldn't continue with the emotionless sex.

[117] On the other hand, People Magazine was initially less than impressed with Lexie and criticized the way Leigh's character first approached her sister, calling it "rude".

"[123][124][125] TV Guide's Adam Bryant praised Leigh's "powerful performance" in Season 6, writing: "The bond that is growing between Lexie and Meredith is nice to see.