Dr. Izzy Stevens
Background
Izzie grew up in nearby Chehalis, Washington living in a trailer park with her mother, who nicknamed her "Cricket". Izzie worked as a waitress as a teenager and had savings for college, but her mother spent all of their money calling psychics, so Izzie ended up paying the vast majority of their bills with her own money. This caused their estranged relationship. At 16, she gave birth to a daughter whom she subsequently gave up for adoption, as she wanted a better life for her daughter than she could give her at 16. When Izzie turned 18, she left home. Her daughter was adopted by a presumably upper-class family that once lived in Santa Barbara. The daughter was named Hannah by the adoptive parents. Izzie donated bone marrow to save Hannah, who was suffering from leukemia. Izzie paid her way through medical school at University of Washington as a lingerie model for a fictional lingerie company called Bethany Whisper (a play off Victoria's Secret). She also worked as a candy striper before her arrival at Seattle Grace.
Izzie is kind and compassionate, often to the extent of getting too emotionally involved, and frequently goes out of her way to help her patients, disregarding rules and protocol if she needs to. This would later prove to be her downfall in season two, when she falls in love with her heart patient Denny Duquette. Shortly after she accepts his marriage proposal, he dies from a blood clot, leaving Izzie devastated and overwhelmed by grief. She then comes to the conclusion that she tends to get too emotionally involved with her patients but still wants to be a surgeon, and will strike an appropriate balance between the professional and the personal.
Season 1
In season one, friendly and eager, Izzie became fast friends with her fellow interns Dr. Meredith Grey, Dr. Cristina Yang and especially Dr. George O'Malley, whom she considers her best friend. Together with George, she manages to convince Meredith to let them move in with her. Not long after, she realizes George’s infatuation with Meredith and encourages him to ask her out.
An ex-lingerie model, Izzie initially struggles with other people’s preconceived notions about her being an incompetent doctor. It is not long before Dr. Alex Karev finds out about her modeling stint, and proceeds to put up copies of her lingerie advertisements in Seattle Grace to humiliate her. Izzie, furious, confronts Alex and reminds him that her modeling paid for all her student loans, while he was still deep in debt.
Season 2
In season two, despite this, she subsequently warms to Alex when she sees through his aloof and callous exterior. She strikes up a tentative friendship with him, to the shock of her fellow interns. Although she denies having any attraction to Alex, she accepts his offer for a dinner date in “Deny, Deny, Deny”. However, Alex has had a rough day prior to that date, and treats her coldly throughout, putting their budding relationship on the backburner. Their relationship is later rekindled when Alex gives her a long, passionate kiss in Joe’s bar.
Due to technical problems on Alex’s part, Izzie’s sexual relationship with him runs into some difficulties. She later catches him sleeping with nurse Olivia, and ends their relationship in “Much Too Much”. Izzie soon finds out that her friends were helping Alex study for his failed boards, and blows up at them for helping him. Even though she ended up helping him and when he asked why she said, "Because, it's what Jesus would freakin do''!". Although she eventually forgives him, she rules out all possibility of forming a concrete relationship with him ever again.
In “Begin the Begin”, Izzie is introduced to a heart transplant patient named Denny Duquette. Although he leaves the hospital after failing to get the heart, Izzie is charmed by Denny’s playful flirtation and sense of humor.
During a bomb scare at the hospital, Izzie realizes that she needs to step up and do what she wants, not stand back and watch Meredith and Cristina be the center of attention. She accosts Alex and proceeds to have sex with him in a linen closet, and several times more over the course of the day. But when Denny is readmitted to Seattle Grace in “What Have I Done to Deserve This?” after suffering cardiac dysrhythmia, Izzie brushes Alex off for him. Alex is jealous of Izzie’s concern for Denny, and tries to get Denny to back off by telling him that there was a good chance that he would die from his failing heart, and that Izzie would never try to end the relationship. Izzie confronts Alex about what he said, and he replies that she cannot get involved with her patients. However, Izzie realizes that she doesn't have to settle for Alex and breaks up with him.
After George has a disastrous sexual encounter with Meredith, he moves out of their house, to Izzie’s disappointment. She makes repeated attempts to find out his new living arrangements, but he refuses to tell her. However, he eventually moves back and frequently has his new girlfriend, Dr. Callie Torres, over. Izzie considers Callie a freak, and makes it clear that she does not like Callie’s presence in his life. Her frequent snide remarks about Callie and George’s reluctance to take Izzie to task for it is a factor in the couple breaking up later on.
Denny undergoes a surgery to get a left ventricular assist device (LVAD) installed, so that he will have a better chance of survival. Denny signs DNR (Do Not Resuscitate) papers, which infuriates Izzie and leads her to have an emotional break down. When Izzie finds out that Denny lost out on a donor heart by a mere 17 seconds, she implores Denny to let her make his condition worsen so that he will move up the donor list. He initially refuses her proposal, as her medical career would be over, but relents after Izzie breaks down, begging him. She cuts his LVAD wire, and seeks the help of the interns to help prevent Denny from dying. Cristina informs Izzie that Denny’s surgeon, Dr. Preston Burke has been shot and is currently fighting for his life, Izzie panicks, completely at a loss. As the interns’ tensions rise while Denny lay dying, he proposes to a shocked Izzie in the midst of the mayhem.
Bailey walks in on the interns with their dying patient. Chief Webber bans them from all surgeries until someone admits to cutting the LVAD wire, while Dr. Alex Karev invites cardiothoracic surgeon, and Dr. Burk's rival, Dr. Erica Hahn to replace Burke for Denny’s heart transplant because Burke is still recovering from his gun shot wound. Denny’s transplant is successful, and Izzie agrees to marry him when she visits him after his surgery only for him to die hours later leaving Izzie devastated. Alex is forced to physically pick Izzie up off of Denny's body, and tells her that the body was no longer Denny, the man she loved. She subsequently admits to cutting the LVAD wire, and announces that she was leaving the surgical internship program.
Season 3
In season three, Izzie is wracked with grief, and is not able to get up from the floor and change her dress. Meredith later convinces her to get up and helps to change her. She later bakes hundreds of muffins to distract herself. Alex, manages to convince their resident Dr. Miranda Bailey to talk to Izzie, to stop her compulsive baking. Denny’s father later requests a meeting with Izzie in “What I Am”, and hands her an $8.7 million dollar inheritance check from Denny. To her friends’ shock, she decides not to cash in the check, and places it on the refrigerator instead. She regards the check as the last vestige of Denny, and is reluctant to part with it until something good could be done with the money.
After witnessing Cristina perform a running whip stitch in the OR, an inspired Izzie decides to return to the internship program. Bailey manages to convince the Chief to allow Izzie to return, but she is placed under strict probation, which prevents her from coming into direct contact with patients. She is, however, dissatisfied with the limited medical work she is allowed to do, and frequently tries to push the boundaries of her probation. In a bid to be allowed back into the OR, Izzie deposits the check and uses it to donate $300,000 for an experimental sugery that a patient cannot afford due to their insurance company's refusal to pay. Bailey is hoping that Izzie has donated the money so that she can scrub in on the surgery, but is disappointed to find that Izzie donated it out of compassion for the patient. Although this would normally be seen as good and acceptable, Bailey reprimands Izzie for becoming overly involved with a patient yet again. Later, Izzie donates the rest of the money to fund Bailey’s free clinic – the Denny Duquette Memorial Clinic.
During a ferry accident, Izzie manages to save a man’s life by drilling burr holes into his skull with an ordinary drill, causing an impressed Chief to take her off probation in “Drowning on Dry Land”.
Although Izzie had agreed to let George pursue his happiness with Callie, she is hardly supportive when George announces that he had married Callie in Las Vegas, mocking the size of Callie’s ring, and later telling George outright that he has made a huge mistake getting married and declares to Callie that the marriage is nothing but "a piece of paper." Her antagonism towards Callie drives a wedge between her and George. Izzie tries to apologize for her behavior, but George rebuffs her halfhearted attempt.
Callie kicks George out of their hotel room after voicing her belief that Izzie "has feelings" for George. Depressed and confused, George goes to Izzie's and Meredith's house with a bottle of bourbon. Izzie and George promptly get drunk, and sleep together. The following day, Izzie learns that George does not remember their intimacy from the previous night. It isn't until after having lunch with Callie and her father that George remembers what had happened. George confronts Izzie in a linen closet at Seattle Grace but storms out in a surge of guilt. He later convinces Izzie, who wants to tell Callie, that the incident must remain their secret.
While dealing with the aftermath of sleeping with George, Izzie is visited by the parents of the daughter she gave up for adoption. Hannah, 11 years old, is sick with leukemia and needs a bone marrow transplant immediately. Izzie agrees to donate the bone marrow to save the daughter she never knew, causing her much emotional grief. Dr. Bailey helps Izzie keep Hannah a secret from the other interns, but George becomes worried when he sees Izzie crying, and goes to find her. He stays with her during the bone marrow harvest, putting all other emotions aside to help Izzie. Izzie later confides in George that she has a daughter, and confesses that she needs his friendship to survive. George, still conflicted with his feelings for Izzie and ashamed of betraying Callie, leaves Izzie crying in her recovery room. He returns moments later, realizing that Izzie needs help as a friend. George accompanies Izzie to see her daughter for the very first time, noting that Hannah has Izzie’s eyes and mouth.
Following which, Izzie and George try to pretend that they were both fine, and continue doing things together as friends. An increasingly suspicious Callie begs Izzie to return George to her, prompting Izzie to guiltily withdraw from George. She and George realize that they cannot just pretend that their sexual encounter did not happen, especially when their growing feelings for each other keep getting in the way. This leads George to decide to transfer to Mercy West.
When George receives notice that he has been accepted in Mercy West’s program, Izzie tries to convince him not to transfer. She explains to George that she has no romantic feelings whatsoever for him, which means there is no reason for him to leave Seattle Grace. However, she reveals to him before Cristina's wedding that she has fallen in love with him, to his shock and surprise.
Season 4
Izzie and George start an illicit relationship, only to be found out by Callie and the whole hospital. They then decide that even though they love each other, they should break up because the timing is not right and they discover that they have very little chemistry. They continue to remain good friends. Izzie then decides to try cardiothoracics, much to the dismay of Cristina Yang, who is also vying for the specialty. She gives up on it, finding that it is not her niche. She undergoes a crisis of sorts, one she gets over by asserting her authority as a doctor to a difficult patient and to her interns. When Rebecca returns to Seattle claiming her pregnancy, and while Alex is learning how to cope with being a father, Izzie finds out that Rebecca is not pregnant. Alex tries to take care of Rebecca, but fails when she is rushed to hospital for cutting her wrists. Izzie convinces Alex to leave Rebecca under the care of the psychiatric ward and the hospital. Rebecca's husband tells Alex that she has been sick even since she had plastic surgery on her face and he blames himself for her sickness. When Rebecca was admitted to the psych ward, Izzie later found Alex in his room and said she was sorry about what happened to his mother and Rebecca. She sits next to him on the bed. He starts to kiss her, asking for her to stay with him for one night. Due to his exhaustion and his pain, Alex fully breaks down in tears in her arms. During the same time frame, she is given the keys to the Duquette Clinic as Miranda defers her duties as the clinic's primary physician to Izzie.
Season 5
As a result of the events of the fourth season finale, Alex and Izzie seem to have developed a close relationship, with deeper feelings being hinted at by the situations in the hospital. When Alex found out that Izzie told Meredith about that night, however, he goes back to being a jerk to her, something that reached its climax when he stole Izzie's patient. After heeding George's advice to "use her talents," Izzie managed to convince the patient to let her do the surgery instead of Alex. He gets mad at her for the switch, but later explains himself as Izzie tried to reach out to him again. After a series of events at the hospital makes both Izzie and Alex realize that they still care much about each other, Izzie goes to his room one night and tells him that. She refuses to leave when Alex asks her to, and he eventually kisses her. A week later, Alex asks her whether they will screw other people as well and Izzie gets angry when Alex asks her that. That night, Alex asks Izzie to teach him how to talk about his feelings because he doesn't know how to and she realizes that he only acted that way because he didn't want them to date anyone else but each other. They decide to "go steady", kiss and enter an exclusive relationship.
Izzie's decision to steal a heart for Denny Duquette a year ago comes back to haunt her when the man who was supposed to get the heart that eventually went to Denny comes to Seattle Grace and Erica Hahn tells her if this man dies then she will be held responsible. During this time, Izzie begins to see Denny again, even after the man survives. This troubles Izzie greatly, as she believes she is hallucinating or going insane. After a sexual encounter between Izzie and Denny, however, she resigns herself to the supposed existence of Denny in her life even though she is the only one who can see him. This affected her work and her relationships with Alex, who thinks that Izzie was still coping with her sadness, and George, who thinks something is truly wrong with her. Izzie's relationship with Alex progresses and she decides to break up with Denny and tells him he needs to go. However, Denny reveals to Izzie that the reason why he was "here for her" was because Izzie is sick. Angry that he spent so long with her without telling her, she sends him away.
Desperate to find out if she is sick without wanting to share her secret with anyone, Izzie makes her interns perform any test they have ordered for a clinic patient (which include a blood test, chest X-ray and head CT) on her first under the auspices of teaching. Sadie later comes to her with the results of her blood draw which reveal a simple case of anemia, however it is revealed that her test results have been switched with those of a patient who was misdiagnosed with a probable case of cancer. Shortly after this, Izzie discovers a small lesion on her back, and has a biopsy to determine its cause. She is approached by the dermatologist with the results towards the end of the episode, but they are not revealed to the viewer. Izzie confronts her interns about their incompetence, and sets them the task of investigating and diagnosing the illness of "Patient X", hiding from them that she is in fact the patient they are now working on.
In the episode "I Will Follow You Into The Dark", Izzie is diagnosed by the interns and she has metastatic melanoma (Stage IV). In her case it has spread to her liver, her skin, and her brain and is the probable cause of her hallucinations of Denny. Her survival chances are estimated at only 5%. She's afraid to tell Alex about it, so instead, she chooses to inform Cristina, who eventually tells Alex & Dr. Bailey before performing her first solo surgery on an elderly woman's hernia. The rest of Izzie's friends find out about her illness and she is admitted to the hospital.
In the next episode, "Elevator Love Letter", Izzie has been a patient for a day now, and like she always does when she's nervous, she's knitting. Alex, Meredith, George and Cristina all don't stop by, Bailey is the only one who visits her a few times a day. Before she goes into surgery, she gives permission to harvest her eggs in case she wants to have babies. During surgery, the tumor in her brain was successfully removed by Derek, who was back at the hospital for the first time since he quit. After surgery, Alex comes to visit her, apologizing for not coming sooner. He also informs he has 'snooched' into a cup to fertilize her eggs. He lies next to her in her bed, waiting for her to get better.
Source: Wikipedia.org