Constance Langdon is the next-door neighbor of the Harmons. She is a character in the first season (dubbed by fans "Murder House") portrayed by Jessica Lange.
Constance was born and raised in Virginia, but moved to Los Angeles to become an actress. After objecting to the nudity that was flooding the film industry at the time, her dreams of becoming an actress fell to the wayside.
In 1983, she murdered both her husband, Hugo, and Moira O'Hara (with whom Hugo has cheated with once before) after catching them about to have sex, believing they were having an affair. After disposing of the bodies, Constance fell into a deep depression and began drinking heavily. With Hugo gone and the family's income greatly depleted, the bank repossessed the house and Constance had to move out.
She purported to be gentle and good-natured but was really cunning and rude. She cared very much for her children, even though she frequently resorted to cruel parenting. She also ran a boarding kennel out of her home.
Constance was very concerned with her status and looks. To curb her loneliness, she began a relationship with Travis. In order to restore her formerly upper-class lifestyle, she stole Vivien's jewelry and silverware. When the house fell out of her possession, Constance seduced Larry Harvey, an influential banker who moved into the house after her with his wife and children. After the deaths of Larry's family, Constance moved back into the house with Tate, Adelaide, and Beauregard.
Constance has turbulent connections with many of the inhabitants of the house, but especially Moira. Despite this, it appears the two of them are involved in some sort of plot involving Vivien's pregnancy, as she brings over assorted innards of pig for Vivien, claiming the organs are good for the baby. She may also have some precognitive ability, for example: she entered the house in the middle of the night and keeps Ben from injury during the Pilot and the toxic cupcakes she delivered for Violet actually ended up making one of the intruders violently ill during the home invasion. Even though she is well aware of the dead inhabitants and their fates in the house, she says nothing to warn the Harmon family.
Pilot: Constance introduces herself to the Harmon's as their next door neighbor. She also raids Vivien's jewelry box and is caught by Moira, though Moira does nothing about it.
Home Invasion: Constance bakes two large cupcakes, ostensibly for Violet, adding ipecac syrup to the batter. She spends some time with a handsome young man named Travis. She later assists Tate and Moira in disposing of the dead R. Franklin murder reenactors.
Murder House: 1983 Constance catches her husband Hugo, raping the housekeeper, Moira. Believing they are having an affair she shoots Moira through her eye then shoots Hugo three times in the chest. 2011 She is caught again by Moira stealing silverware from the Harmon's. She tells Moira that she will keep stealing until she has "a full set" to sell on eBay and Moira is "fired for stealing". While walking her dogs she spots Tate through the window of the Murder House's attic and waves to him but he does not wave back.
Halloween: Part 1: Constance is at home with Travis and her daughter Addy. She gets mad at Addy for her flirtations with Travis. Constance argues with Addy over her Halloween costume and finally settles on buying her a "pretty girl" mask. Addy is later killed in a hit-and-run accident and Constance tried to drag her onto the lawn of the house so she would come back in spirit.
Piggy Piggy: 1994 Constance is present when Tate is killed by a S.W.A.T team. 2011 She introduces Violet to a medium named Billie Dean Howard and tries to relate to Violet about her dealings with the dead.
Spooky Little Girl: Constance has an argument with Travis he leaves. Constance later learns from Moira that Tate has fathered one of Vivien's twins. She confronts Tate about this and later proposes to Travis, apologizing for her earlier actions. She tells him the two can raise Tate's child together, to which he tells her he's unsure, as he is still trying to build his acting career. She shoots down his dreams, citing her own experiences. After they argue, Travis leaves again. Constance visits Vivien in the hospital, offering her help during the pregnancy. Constance asks Billie Dean what could result from a human/spirit conception and is told that it could result in the birth of the Anti-Christ who will bring about the end of times.
Smoldering Children: Constance is questioned about Travis's murder as well as the murders of Hugo, Moira, and Beau. Although he did not have a hand in Travis's murder (other than disposing of his remains), Larry takes the fall in order to pay for all his sins. He tells Constance he will be able to endure any punishment as long as she admits she loves him, to which she coldly refuses.
Birth: Constance assists in the birth of Vivien's twins and quickly snatches Tate's child (her grandchild), Michael.
Afterbirth: Constance cautions Ben against bringing Michael back into the house. When Ben dies, she takes it upon herself to raise Michael as her own. Three years later, she has left Los Angeles and is raising Michael in an unknown location. She returns home to find he has murdered his nanny. Constance smirks at the sight commenting "Now, whatever am I going to do with you? "
To Tate Langdon: "Just a smile or a kind word could open the gates to Heaven."
To Moira O'Hara: "I am trying to find some dignity in this situation."
To Moira O'Hara: "Every time I find my heart break in just a sliver for you, I suddenly remember; You brought this all on yourself."
To Vivien Harmon: "He was a model of physical perfection. He was my gift. But I lost him to other things."
To Violet Harmon: "They say when a parent dies, a child feels his own mortality, but when a child dies, it's immortality that a parent loses."
To Violet Harmon: "He's a sensitive boy, you know that; a young man with too deep feelings, the soul of a poet, but none of the grit or steel that acts as a bulwark against... these horrors of this world."
To Violet Harmon: "I questioned my sanity when I first found out, but this house will make you a believer."
To Vivien Harmon: "We need that baby. We need another... sweet child."
Constance Langdon: "At the end of the day... he meant less to me than dog shit."
To Chad Warwick: "Why can't you people just be content with having pets? Why must you subject an innocent child to your perversions?"
To Billie Dean Howard: "Well that's all nice and dandy, but what about the gays I mean, how do we get rid of them?"
To Moira O'Hara: "There's not gonna be any swimming pool you stupid slut!"
To Larry Harvey: "Even dead, even a boy, he’s twice the man you are."
To Detective Granger: "I have grieved enough for two lifetimes. Most people would be broken by the deaths of their children, but my nature would not permit such weakness."
To Vivien Harmon: "I thought those people were supposed to be stylish."
Although Constance stated that she had four children, a fourth child was never revealed. However, in a recent interview with Tim Minear, it was revealed that there was supposed to be a mention of it in Constance's beauty salon speech in the final episode, but it was cut.
Ryan Murphy stated that Constance was to have an albino child in his commentary for Pilot.
She bore many similarities to the character Minnie Castevet, the strange and eccentric neighbor portrayed by Ruth Gordon in Rosemary's Baby. Both characters try to obtain babies destined to become malefic entities from their respective mothers.
Constance claims to be distant cousins to the DeLongpres of Virginia.  "DeLongpre" happens to be the last name of former Supreme, Mimi DeLongpre.