||Meredith Grey, played by Ellen Pompeo
Meredith Grey was born to be a surgeon. Living in the shadow of her mother Ellis Grey, a world-renowned surgeon, Meredith is trying hard to live up to the precedent her mother set. But things are complicated between Meredith and her mother: Ellis has advanced Alzheimer's disease and frequently doesn't remember her past ... or her daughter. Meredith tried to hide this fact as long as she could, but the other interns and the Seattle Grace staff soon caught wind of her mother's condition when Ellis was brought into the hospital for tests.
As if her life wasn't complex enough beforehand, Meredith, the night before her first day on the job, slept with Dr. Derek Shepard not knowing that he would be her boss the next morning. Though a relationship between an intern and an attending is taboo at the hospital, Derek pursued Meredith and the two soon began an ill-fated relationship tested by the other interns, especially when they thought Meredith would be favored, and was forced to "jump through hoops" by her senior resident, Dr. Miranda Bailey. Meredith's feelings for Derek were thrown into a tailspin with the arrival of his wife, Dr. Addison Shepard, and she was devastated when he chose to stay with his wife instead of leaving her for Meredith, despite his obvious affections towards her. Meredith tried to move on with her life, but the pain of seeing Derek and Addison together day in and day out made the wound slow to heal.
Aside from Derek and dealing with her mother's illness, Meredith's home life is relatively calm ... at times. She lives in her mother's house along with Izzie and George and though the three got along like family, her home life became complicated when Meredith and George slept together. Meredith's mounting emotions from confronting her father and the loss of Derek spilled out at once, and ended up crying while having sex with George. This angered George and he soon moved out of the house to get away from Meredith. Since then, their rift has been slow to mend.
As a doctor, Meredith is quick on her feet and caring towards her patients. Though her emotions sometimes get the best of her, she remains cool and calm in the daily life-or-death situations she faces. She doesn't always help a patient by the book, or to the likings of Dr. Bailey, but she's good at what she does and works hard to follow in her mother's footsteps.
||Derek Shepherd, played by Patrick Dempsey
Nicknamed “McDreamy” by the interns, Dr. Derek Shepherd, a world renowned brain surgeon, moved to Seattle from New York and is currently a resident surgeon at Seattle Grace Hospital. During the pilot episode, Derek slept with Meredith after meeting her at a bar, and fell for her shortly after. Though he finally convinced Meredith to start a relationship with him, despite her early objections, their blossoming relationship was ill-fated, especially after the arrival of his wife, Dr. Addison Montgomery Shepherd.
Derek is good at what he does, and he knows it. At work, Derek is in line to be the next Seattle Grace chief-of-staff, competing with fellow surgeon Dr. Preston Burke. Despite the obvious rivalry between the two, Derek and Preston remain good friends.
With Addison in the picture, Derek made the tough decision to break it off with Meredith and try to make his marriage work. However, his decision devastated Meredith, and though he tries to get his marriage back on track, he still has obvious feelings for Meredith and has a hard time getting her off of his mind. As season 2 ended, Derek and Meredith secretly rekindled their relationship and now Derek waits in the balance as Meredith must choose between him and Dr. Finn Dandridge.