Maggie lost her family to a vampire horde, she was orphaned and was one of the few humans who were left.
In Beat the Devil, while Sam, Dean, Castiel, and Gabriel are trekking through Apocalypse World looking for Jack and Mary Winchester, they come across Maggie and her friend, Floyd, who are attempting to fight off a rabid vampire. After Sam kills the monster, Maggie and Floyd explain of the monsters lack of food causing them to turn rabid, and how their group was heading through a tunnel when they ran into a nest of them. Maggie and Floyd were the only survivors. When they explain they were trying to get to the Dayton outpost that Jack and Mary had set up, Sam promises to keep them safe and get them there.
After crossing through the tunnel and witnessing a vampire kill Floyd and rip out Sam's throat, she attempts to comfort Dean, to no avail. They make it to the camp and is part of the security when Sam shows up, having been resurrected by Lucifer, and sees Lucifer follow behind.
In Exodus, Maggie joins in the group of people that Dean and Sam take to the rift in an exodus. She crossed over into the Men of Letters bunker on the main Earth and is one of many people whom Rowena MacLeod is confused by their entrance.
In Let the Good Times Roll, Maggie is found dead by Mary Winchester and Bobby Singer near the bunker with her head bashed in. Despite the fact that Maggie's murder appears to be done by a human, the Winchesters investigate and discover that she was secretly seeing a young man named Nate at a nearby gas station. Enraged over Maggie's death, Jack attacks Nate, but Nate proves to be innocent.
After the unexpected return of Lucifer, Jack, who feels guilty for not being able to protect Maggie, requests that Lucifer resurrect her. Jack takes Lucifer to the bunker where Maggie's body is laid out on a table awaiting a Hunter's Funeral. Despite hesitation on Lucifer's part, he resurrects Maggie and then departs with Jack. The Winchesters and Castiel return and are surprised to see her alive again.
In the aftermath of her resurrection, Sam questions Maggie on who killed her. Maggie admits that she doesn't know, all she saw was her killer's glowing red eyes. Sam realizes that Lucifer killed Maggie and confronts Lucifer with this. Jack forces Lucifer to admit that he murdered Maggie when she encountered him scouting out the bunker, enraging Jack and turning him against his father.
In Stranger in a Strange Land, Maggie treats the injuries of another hunter who fought a Rawhead and seems fascinated by a tooth she pulls from the man's back. Sam asks Maggie to help him hack into traffic cameras to track a nest of vampires, but she doesn't know how, forcing Sam to do it himself.
Maggie later joins Sam's team to rescue Castiel from the demon Kipling. Alongside Jack, Maggie is captured by Kipling's demons and held hostage during the meeting. When Bobby and Mary burst in, Mary has Maggie take cover behind the bar and hands her an angel blade to defend herself with which Maggie nervously guesses is used by stabbing the pointy end into the bad guys. As Mary is strangled by a female demon, Maggie suddenly kills the demon from behind with her angel blade, saving Mary's life. She is then overpowered by another demon and struggles with him briefly until Sam kills Kipling and orders the other demons to stop. Maggie watches in shock as Sam forcefully abolishes the position of Ruler of Hell and the demons flee their vessels in their smoke forms.
During Nightmare Logic, Maggie went on her first case in what she thought involved a ghoul and she was very excited as she investigated the area while recording the event with a camera. However, she was attacked by a manifestation and taken captive by Neil, one of Michael's enhanced monster assassins. Neil started to drain her blood and created manifestations of Apocalypse World vampires, Maggie's greatest fear due what the vampires had done to her family. As she went missing, Sam and Dean decided to find her and tracked her location where they found Bobby Singer and Mary on the scene since Maggie contacted them before capture. For most of her captivity, Maggie remained as her blood was drained by a rig. She was found by Sam and alerted him of the threat before he destroyed the illusion and freed her. Maggie left the area with her friends and was welcomed back to the bunker as she recovered. Maggie later told Dean that she wanted to get back to hunting after she was normal.
In Nihilism, Maggie takes command of the hunters rushing to Kansas City to aid in stopping Michael's monsters. Sam calls Maggie and asks her to pick up the Impala and Garth, but they learn that the monsters are heading towards the bunker instead. Maggie rallies the other hunters to create a roadblock to stop the monsters from reaching the bunker, but a vanful manage to get past the roadblock. Maggie and the other hunters abandon the roadblock in favor of defending the bunker, unaware that one of the group has been replaced by a shapeshifter who leaves the door open for the monsters. Maggie struggles with the other hunters to fight off the monsters until Jack uses the power of his soul to disintegrate the monsters. Maggie later tells Sam that they have been getting reports of Michael's army disbanding with Michael unable to command them in his current condition.
In Ouroboros, Maggie is left in charge by Sam while Team Free Will 2.0 are out on a hunt with Rowena. Sam later calls Maggie who tells him that the lore states that a gorgon can only be killed via decapitation with a silver blade. Maggie updates Sam that his mother is on her way from home from a case in Oregon and that things are quiet at the bunker.
After Michael escapes Dean's mind and possesses Rowena MacLeod, he slaughters all of the hunters in the bunker but Maggie. As a terrified Maggie runs to Sam, Michael suddenly smites her from a distance, killing Maggie. Her death is avenged shortly thereafter when Jack kills Michael.
During Peace of Mind, it is mentioned that Maggie was given a hunter's funeral along with the other deceased hunters. Her death is shown to weigh heavily on Sam and Jack who are both shaken by the memory of her.
She is indirectly mentioned in Don't Go In The Woods. Sam tells Mason Romero that even if people knew about the supernatural and knew how to do get against it that they could still die. This shows Maggie's death still plagues him.
Maggie is a nervous, but brave and caring young woman. Despite the traumas she has experienced in her life, Maggie doesn't let it stop her. While battling demons Maggie nervously hid behind a bar and armed herself with an angel blade given to her by Mary Winchester for self-defense, but didn't hesitate to emerge from hiding to save Mary's life by killing a demon, putting herself in harm's way at the same time. After being kidnapped by the djinn Neil on her first solo hunt, Maggie was eager to get back to hunting rather than letting the experience stop her. She grew confident enough to command several other hunters in battle with Michael's monsters and to stand her ground against their overwhelming force.
- Season 13
- Season 14
- Maggie is the last person killed by Lucifer before his own death. Ironically, he was forced to resurrect her by Jack.
- While preparing to resurrect Maggie, Lucifer states that those who are resurrected don't always come back the same, echoing the words of Azazel about Sam in All Hell Breaks Loose - Part 2. Despite this, Maggie shows no obvious changes in personality.
- Maggie is the last person killed by both Lucifer and the Apocalypse World Michael before their respective deaths. Unlike her death at the hands of Lucifer, Maggie is not resurrected after Michael kills her.
- Maggie is the only character to be killed by an archangel, only to be resurrected by an archangel, only then to be later killed again by another archangel. Those who were killed by one and came back were resurrected by other means: God resurrected Castiel after the first two times he's killed by one, Castiel is resurrected by the Shadow after to being killed by Lucifer for the second time, and Rowena is resurrected by her Resurrection Seal both times Lucifer killed her.