After her brother Clay left the family as a teenager, Whitney was left to care for their ailing mother, Mrs. Miller. In 2008, Whitney received a call from Clay which culminated in the siblings getting into a fight and not speaking for some time. A while after her fight with Clay, Whitney, her boyfriend Mike and their friends Wade, Amanda and Richie head off to Crystal Lake, where Wade had been told that a large amount of wild marijuana grew. After getting lost in the woods around Camp Crystal Lake, Whitney and her friends set up camp. When night falls, Whitney learns about Jason Voorhees and his mother Pamela Voorhees from Wade, with it being rumored that Jason now stalks the woods.
Not believing Wade's tales, Whitney convinces Mike to go explore the woods with her and the two stumble upon an old house filled with assorted junk. Shortly after Mike finds a locket containing an old picture of Pamela Voorhees, who Whitney resembles, the pair find the severed head of Pamela in a shrine-like construct. After Mike drops Pamela's head in shock, Whitney realizes someone is outside. As Mike goes to investigate who is lurking around the house, he and Whitney are attacked by Jason who begins stabbing his machete up through the floor, severely injuring Mike.
Getting to higher ground, Whitney tries to save Mike, only to witness him be murdered by Jason, who bursts up through a trapdoor and drags Mike away, finishing him off underground. With Mike dead, Whitney flees back to camp, with Jason in pursuit. Reaching the campsite, Whitney finds Wade missing, Amanda dead and Richie stuck in a bear trap, which she tries to help him out of it. When Jason appears and kills Richie with his machete, he prepares to kill Whitney, but relents when he notices her resemblance to his mother. Taken away by Jason, Whitney is shackled to the wall in his underground lair and given the locket containing the picture of Pamela that Mike had showed her earlier.
Though the authorities search for her and her dead friends for some time, Whitney is never found and the authorities come to believe that she may have simply ran off with Mike.
Kept captive by Jason for six weeks, Whitney, after Jason kills three more people (Donnie, Nolan and Chelsea) is given a bag belonging to her brother by Jason. Finding a missing persons poster of herself in the sack, Whitney realizes Clay is searching for her and, also discovering Wade's broken GPS, tries to use a piece of it to pick the locks of her chains.
Succeeding in picking the locks, Whitney escapes Jason's lair (finding the bodies of her friends in one room) and stumbles through the woods, eventually finding the summer home of Trent Sutton. Before she can call for help, Whitney is found by Jason, who drags her back to his lair and chains her up again.  
Later, Whitney, hearing people in the cabin above Jason's lair, calls out for help. Finding the trapdoor that leads underground, Clay and his friend Jenna discover Whitney and break the chains holding her. Fleeing with Clay and Jenna when Jason arrives, Whitney, while climbing through a tunnel with Clay, witnesses Jason kill Jenna by impaling her with his machete.
After Jenna is murdered before she is able to get out of there, Whitney and Clay climb through the tunnel and reach an old overturned bus where Jason attacks and begins beating Clay. Despite Jason's attacks, Whitney and Clay manage to flee to a nearby barn. Followed by Jason, Whitney, when he attacks Clay, distracts the killer by pretending to be his mother.
With the ruse working and Jason confused, Whitney helps Clay wrap a chain around Jason's neck after her brother sets a bear trap off on the killer's shoulder. Feeding one end of the chain into a nearby woodchipper, Whitney and Clay hang Jason, but fail to kill him due to the rafter the chain is suspended from breaking. When the recovered but restrained Jason renews his attacks, Whitney stabs him deep in the chest with his own machete.
With Jason seemingly dead, Whitney and Clay take him to a pier at Crystal Lake in the morning. After dumping Jason's body into the water, Whitney and Clay toss the killer's hockey mask and Pamela's locket into the lake as well. For some unknown reason, she begins to cry. With things seemingly over, Whitney is taken by surprise when Jason comes crashing up through dock and grabs her. Her fate (along with Clay's fate) is unknown. 
- Whitney and her brother Clay Miller are named after Jason Voorhees' creator, Victor Miller.
- Whitney can be considered a version of Ginny Field due her abilities to seem like Jason's mother.
- Her ultimate fate is an homage to three first original film endings.