[2][3] Introduced as a surgical intern at the fictional Seattle Grace Hospital, Karev evolves throughout the series, obtaining the position of resident and eventually specializing as a pediatric surgeon.

His relationships with colleagues Meredith Grey (Ellen Pompeo), Cristina Yang (Sandra Oh), Izzie Stevens (Katherine Heigl) and George O'Malley (T. R. Knight) form a central part of the show's early dynamics.

It received polarized reviews from fans and critics alike, who were divided on the show's handling of Alex's exit, but many largely felt it made sense given the circumstances of Chambers' abrupt departure.

Initially, he made a poor impression on his fellow interns, Meredith Grey (Ellen Pompeo), Cristina Yang (Sandra Oh), Izzie Stevens (Katherine Heigl) and George O'Malley (T. R. Knight).

Alex confided in Izzie about his father's heroin addiction and abusive behavior, revealing his motivations for becoming a wrestler to protect his mother.

At the end of the first season, George contracts syphilis from Alex through their mutual involvement with nurse Olivia Harper, leading to significant animosity between the two.

After recovering, Alex focuses on his pediatric career and begins treating children, showcasing his talent in handling young patients.

However, their relationship is short-lived as Alex's ambition leads him to sabotage Meredith's Alzheimer's clinical trial in an attempt to secure the position of Chief Resident.

He passes the boards, and Dr. Webber informs him that Johns Hopkins Hospital, the top program in the country, has been impressed with him and created a position for him in pediatric surgery, which Alex accepts.

However, when Arizona yells at him and takes his place on a plane that later crashes, Alex decides to stay at Seattle Grace, realizing his loyalty to his colleagues.

That same night, Alex kisses Jo at April's wedding, expressing his desire to start a family, but is deeply upset by his father's death due to Ross' error.

After completing his fellowship in Pediatric Surgery, Alex is offered a job at Dr. Oliver Lebackes' private practice, where he would have more flexible hours and a large salary.

He is rehired at Grey Sloan as a full-time attending pediatric surgeon and takes over Arizona's position when she begins a fellowship with Dr. Nicole Herman.

Fearing that Jo's past would be exposed during the trial, potentially alerting her abusive husband to her whereabouts, Alex decides to take a plea deal, which would result in him going to jail for two years.

When Alex finds him at a conference, he considers confronting him but ultimately decides against it, choosing not to risk Jo's safety or his own by exposing her identity or escalating the situation further.

Initially angry that she is fine despite his difficult childhood, Alex ultimately forgives her after talking with Jo and invites her to Seattle for his wedding.

Jo then learns that her birth mother lives in Pittsburgh and visits her, but upon returning, she becomes distant, stops going to work, and worries Alex.

Additionally, Alex assists Meredith in committing insurance fraud to save a patient's life, which results in him being fired from his position as the head of pediatric surgery.

Alex Karev, portrayed by Justin Chambers, was not originally included in the pilot episode of Grey's Anatomy, which was filmed in March 2004.

On January 10, 2020, Chambers announced his departure from the series after 15 years, stating that he wanted to pursue other acting opportunities and focus on his family.

[6] The American Broadcasting Company (ABC) characterized Karev as "honest" and someone who "always tells it like it is," while also noting his weaknesses, such as his blunt mouth, punctuality issues, and being a "smart-ass".

[7] Grey's Anatomy creator Shonda Rhimes commented on Karev's complexity, saying, "I love that we have a character who can do something wonderful but still be a selfish cranky ass about it.

[9] Initially described as a "superficial sleazeball" who evolves into a "nice guy and a talented doctor with an amazing bedside manner", Karev's journey also saw him become a love interest for Katherine Heigl's character, Izzie Stevens.

[10] His character development in the Season 4 was noted by DVD Verdict, which stated: "Love him, hate him, or both, Karev speaks his mind, rough edges and all.

[13] While Stevens departs in Season 6, series creator Shonda Rhimes expressed an interest in bringing closure to both characters' storylines.

He consistently hurts Izzie and treats others poorly, yet over 10 seasons, Alex evolves in a "slow and realistic" way into a genuinely good person.

Alan Sepinwall, a former columnist for The Star-Ledger, criticized Alex's flirtation with Addison Montgomery, arguing that "he should take interest in a woman's specialty and respect his boss without getting in her pants.

Chris Monfette of IGN noted the emotional depth added to Alex's character in Season 5, especially through his relationship with Izzie Stevens.

"[15] Regarding his career as a pediatric surgeon, Examiner acknowledged Alex's "child-like innocence and need for acceptance," which, despite his rough exterior, helped him connect with children on various levels.

The publication also explored the roots of his "major trust issues," linking them to his tumultuous childhood, including the physical abuse from his father, his mother's mental illness, and the instability of being shuffled through 17 foster homes over five years.