 The five characters who are first introduced in the series premiere , as surgical interns , are Grey , Karev , O 'Malley , Stevens , and Yang . They are initially mentored by Bailey , a senior resident who becomes the hospital 's Chief Resident , and later an attending general surgeon , in season six . The surgical program is initially headed by the Chief of Surgery , Richard Webber , who has a pre @-@ existing personal relationship with Meredith , having had an affair with her mother when Meredith was a child . In Webber 's employ are attending neurosurgeon Derek Shepherd , dubbed ' McDreamy ' by the residents , and attending cardiothoracic surgeon Preston Burke . Shepherd is introduced as Meredith 's love interest , while Burke begins a relationship with Yang . 
