In Pilot, Dorothy was first seen at Mystic Falls High School, talking with the new student and her elder brother, Stefan Salvatore, demanding to know why and what is doing here. Caroline saw them together and ask Dorothy if they know each other and if they have been dating, and Dorothy simple shrug, before going over to Elena and Bonnie. In history class, Dorothy sees Stefan staring at Elena, because of the resemblance of Katherine Pierce. Dorothy sent him an knowing look before receiving an text from Bonnie. At the Mystic Grill, talking with Caroline and Bonnie, wondering what is up with her and Stefan, Matt and Tyler joining them. Dorothy looked up and saw Stefan and Elena arriving. Dorothy got up and went pass them, before whispering something into Stefan's ear, before getting out of the Grill, leaving her confused friends.
At the Salvatore Boarding House, Dorothy was arguing with Stefan, as Zach bursts into the room, interrupting the conversation with holding an paper with two deaths. Dorothy shot Stefan an look, as Stefan states he is handling it. Dorothy asks if Damon was in town. Stefan replies no. Dorothy watches Stefan as he pulled out an picture Katherine Pierce, disgusted Dorothy left the room. Next day in Mr Tanner's class, Stefan contradicts him as Dorothy back him up, knowing that they both live through the Battle of Willow Creek and Mr Tanner ends up humiliated. Dorothy sent Stefan an wink before leaving the class, Bonnie and Elena catches wink, and asked her about it later.
At the woods, Dorothy heard the conversation between Stefan and Elena on the bridge before hearing something behind her. She turned around and sees her elder brother, Damon. Damon asks what they are talking about, Dorothy simple replies use your ears, Damon smiles before replying that he has miss her. Dorothy replies you are my favourite brother, before walking off, not wanting to interrupt her brother's meal. At the Salvatore Boarding House, Dorothy was in her room, when Stefan comes in, saying that Vicki Donovan was attack, and Dorothy knowing that Damon had attack her, that an crow comes in and turned around to see Damon standing there. Stefan asks why Damon has come back but Damon does not answer.
Dorothy stays silent as she watched her two brothers talk, knowing that Damon is provoking Stefan, and Stefan vamps out, lunging at Damon and out of the room, breaking her window, she was down and sitting on the ledge next to Damon. Damon continues to taunt Stefan, before handing back his daylight ring, before throwing Stefan at the garage door, and warning not to mess with him again. Dorothy got off the ledge and went into her room, to order an new window glass panel.
In The Night of the Comet, Dorothy skip school by catching up with Damon at the Salvatore Boarding House, when she heard an car coming, and knock at the door. Dorothy saw Elena coming in and spotting her and Damon, Damon looking curious. Elena asks what Dorothy is doing here, and Damon simply replies sister what are you doing here. Elena was shocked, as Damon introduce himself as Stefan and Dorothy's older brother and mentioning Stefan's ex-girlfriend, Katherine, and that Elena was an rebound of Stefan's. Dorothy looks amused and also worried and concern that Damon was feeling something for Elena, feeling an sense of Déjà vu of when Damon and Stefan had feelings for Katherine.
Lucky Stefan arrives home, and was surprise to see them there, and coolly escorts Elena from the house. Dorothy left the house, knowing that Elena would want some answers, as she went to Elena's house and explain.At the night of the comet's appearance, Dorothy was seen by Caroline talking to Damon about the feelings she has, the Déjà vu feelings with Katherine, Damon and Stefan. Damon simply replies that dont worry, before vanishing and Caroline asks how does she knows Damon, and Dorothy simply replies family, before leaving Caroline. Dorothy was up on the rooftop when Damon came up with Vicki, Dorothy was disgusted and went over to help Vicki but Damon hold her back seeing how long Stefan can find them. She left leaving her brother to his fun.