Mark was born in to upper-class, but emotionally distant parents in New York City. While working on a case involving a man's sleepwalking and his daughter's subsequent insomnia, Mark revealed that his own parents would often go out at night, leaving him to care for himself. As a result, he would turn on all the TVs and every light in the house, even those in the closets, but still couldn't sleep. Later, he revealed that he and Derek Shepherd were childhood friends and when Derek's mother, Carolyn , saw how lonely he was, she encouraged Derek to bring him home. This led Mark to develop a family relationship with the Shepherds, and become like a brother to Derek. When Derek's mother visited, she revealed that a year-old Mark once put Derek's favorite frog into the microwave, to which Mark replied that he never pressed start.
Mark Sloan : Derek and I always did have the same taste in women. Meredith Grey : Excuse me? Mark Sloan : You're Derek's lusty intern right? I've heard about you all the way back in New York. You're famous.
Mark Everett Sloan ,  M. Created by showrunner Shonda Rhimes , the character was introduced in season two as Derek Shepherd 's best friend who caused the end of Shepherd's marriage by sleeping with his then-wife, Addison Montgomery. He moves to Seattle in season three to make amends with Derek and becomes Seattle Grace Hospital's new plastics attending , after which he is dubbed " McSteamy " by the female interns for his good looks. Mark's focal storyline in the series involved his romantic relationship with Lexie Grey Chyler Leigh , one of the interns who were on his service when they started dating.
May's season finale crash claims yet another victim as Seattle Grace says goodbye to one of its own. So many things were weird: Lexie was dead! There were new interns and residents! Cristina was away working in Minnesota! Karev was headed to Johns Hopkins! There was no sign of Kepner or Arizona! Bailey was deliriously happy! Derek and Callie were shattered with grief! Sloan was laying there on life support!