|Portrayed by||Katie Jarvis|
|Introduced by||John Yorke|
|First Appearance||9 February 2018|
|Address||31 Albert Square|
Hayley is first seen in Walford taking photos of Stacey and Martin Fowler. Whilst in the café, Hayley looks through her phone and answers a phone call, asking if the caller had received any photographs. She insults Martin to the caller, reassuring them that she knows what to do next.
Stacey is seen by Hayley and Martin's sister Michelle Fowler putting her children Arthur and Hope Fowler in a taxi. Michelle runs to Martin to tell him she is taking the kids. He stops the taxi by jumping in front of it, Stacey gets out of the car and Martin forbids her from taking the kids anywhere. Stacey explains that they are going to pick Stacey's six year old daughter Lily up from school and then go back to Brighton to see Stacey's mother Jean for the weekend. He again tells her no and that she can't make decisions like that without his consent. The Ahmeds get involved after hearing Stacey and Martin argue; Arshad Ahmed then tells Martin, after being told to back-off, that he won't. He accuses Stacey and Martin of abusing their children, Martin apologises and Stacey goes to pick Lily up from school. All of this is filmed by Hayley. She decides to flirt with Martin. When asked by Stacey who she is, she explains that she is her cousin and that Kat sent her. Martin decides that he has had enough of Stacey and sends an email to a solicitor to get custody of Hope and Arthur, however, he changes his mind and (when round Stacey's house) hacks into her email and tries to delete an email from his solicitor. Stacey catches him and after he explains himself, she calls a solicitor when he leaves. Martin spends time with Hayley and she encourages him to take Hope and Arthur longer than it was agreed with Stacey. Hayley invites Martin, Arthur and Hope to her home and makes them a dinner of nuggets, chips and jelly. She explains that she feeds this to her son, Tyler, all the time and it's fine. However unknown to Martin, Tyler does not exist. She then starts a jelly fight with Martin in front of Arthur and Hope and Arthur laughs . Stacey rings Martin but he ignores her calls, so, she rings the police and they arrive on Hayley's doorstep looking for Martin, Hope and Arthur. Stacey admits to Hayley later that she felt guilty at calling the police because of the look on Arthur's face after it happened, but Hayley reminds her that she shouldn't go soft - Slaters stick together. Stacey's nan Mo then comes down after changing Hope and says you can tell she’s a Slater because of how much and how quickly she’s filled her nappy. Stacey decides to let Martin see the kids after seeing how much they mean to him. Martin is invited back into the house to talk about arrangements for the kids with Stacey.
Hayley introduces herself to Martin at his stall on Bridge Street and helps herself to an apple. Later in the café, Hayley distracts Martin when he is looking after his daughter, Hope and Stacey catches Hayley kissing Martin. In Martin's absence, Hayley whispers to Stacey her identity as it was unknown to Stacey that Hayley was in fact her cousin. Martin meets up with Hayley whilst he is looking after Hope and Arthur while Stacey collects Lily up from school. Hayley encourages Martin to keep the children out for longer, disobeying Stacey's instructions. Hayley pretends to defend Martin in front of Stacey when she collects Arthur and Hope with police presence due to Martin not returning them at the time agreed.
Hayley arrives in Walford once more, asking Mo for her share of money from the sale of the SIM cards. When Hayley demands her money, Kat forcibly orders her to leave Walford. It is then noted that Hayley is currently homeless and after spending the night sleeping rough, Stacey's mother Jean invites Hayley indoors where she opens up to Jean about her upbringing and being excluded from the Slater Family. Hayley is barred from The Queen Victoria when Linda Carter finds Hayley slept in the same bed as her husband Mick Carter; it was then revealed Hayley only did this to try and split up Mick and Linda after being paid by Stuart Highway, who used Mick's money to pay her. Whilst Martin is trying to reconcile with Stacey, he discovers that Hayley and Stacey are related and that he was 'set up'. It is later revealed that Hayley is pregnant, despite heavily drinking, but by binding her stomach she is hiding her pregnancy. Hayley befriends an 16 year old homeless girl on the tube, Brianna, who steals money from Hayley that she conned out of a man named Craig, by making him believe she was a prostitute. Brianna notices that Hayley has a baby bump and asks her how far on she is.
The next day, Jean finds Hayley and she tells her that she can move into Stacey's house alongside the rest of the family, like Jean, Stacey, Stacey's cousin Kat Slater, their Nan Mo, Stacey's kids Lily, Arthur and Hope and Lily's auntie Whitney Dean and her sister Tiffany Butcher. A while later in the Queen Vic, Hayley goes to the bathroom and raps a bandage round her stomach so no one will suspect that she is pregnant, however a woman warns her that it is dangerous for the baby, so Hayley stops.
On the night of the Royal Wedding, after Mo and Kat give Hayley a makeover, Jean passes her an umbrella as Kat and Mo plan to tip water on her. Hayley then goes outside to confront them and they stop. She then heads to a hotel room outside of Walford where it is reveled that Kat's husband Alfie Moon is the father of her unborn child after they had a on night stand. The pair talk and Alfie asks about Kat because Kat's son Tommy (who is the biological son of Alfie's brother Michael Moon) and Kat and Alfie's twin boys Ernie and Bert need to see their mum as Aflie is currently raising them after a fall out with Kat - which has made Kat refuse to even see her boys. Alfie tells Hayley he loves Kat but Hayley tells Alfie she thinks the baby is a girl and she could boss her big brothers around and Hayley will raise them as her own. However Alfie replies by telling Hayley that Kat is the boys' mother, not her. Hayley gets mad and wants to have an abortion but Alfie tells her not to but later changes his mind after Hayley talks him round. Alfie gives her the money and the next day Hayley makes an appointment at the hospital for a termination. Hayley then gets drunk and turns up late to her appointment, which makes them refuse to see her. She then makes a new one but changes her mind after Kat tells her she's a good person really. A few weeks later Hayley is shocked when Stacey announces that her and Martin are back together and he will be moving back into the house. The Slater's then get an even bigger surprise when an envelope is put through the letter box saying Slater's. They all don't know if to open it or not and Hayley tells everyone that she is the only Slater. While pointing to Tiffany, Stacey, Mo and Jean, she arrogantly says "Fowler, Harris, Walters - oh and Buchard" to prove a point that she should open the letter as she is the only Slater in the house. But Tiffany very sarcastically replies to Hayley saying "It's Butcher, actually".
Stacey open's the letter and to their surprise, it is the key's to Charlie Slater's old cab, with a note reading telling them that Charlies friend had the cab and he promised Charlie that when he retired he had to give the cab to the Slater's. Hayley tells Stacey she can fix it but she doesn't believe her so Hayley goes to see fellow mechanic Keanu Taylor where she asks if there is any jobs, however she didn't really want a job and was just trying to destract him while she stole some tools to fix her Uncle Charlie's cab. Later on she uses Tiffany's laptop so she can go online and see if anyone is interested in buying the cab. Tiffany spots her and this causes them to argue. Stacey pulls the pair apart but Tiffany goes to slap Hayley which causes another fight to break out. Stacey pulls them apart once again and while Tiffany's back is turned, Hayley eats her piece toast - which makes Tiffany mad. Since the Slater Family house is a bit over crowded, Martin gets annoyed with everyone. He then gets ready to go in the shower but realizes Tiffany is in. When Martin asks her is she is done, she replies "in washing my hair". Martin then comes down stairs and Tiffany comes out the shower, just as Mo runs up the stairs to use the bathroom. When the Bathroom is finally free, Martin goes in the shower but is disturbed when Jean walks in. She then runs down stairs and Martin goes after her. Jean runs into the kitchen where everyone is and Martin explains what has just happened. Tiffany laughs, as does everyone but Jean says "To be fair Martin, I didn't see much". Everyone laughs again and Kat replies "Poor Stacey". Martin goes to turn away and Kat pulls down his towel, which is covering his body. Everyone screams and Tiffany covers her eyes but Stacey grabs the cloth and puts it over Tiffany's eyes. Martin goes up stairs to resume his shower and get ready. When he comes down stairs into the Kitchen he spots Lily on Tiffany's ipad and tells her she should play outside and get some air in her lungs because she looks pasty. A few minutes later, Lily comes downstairs tanned as Tiffany covered her in fake tan because Martin said she looked pasty. Martin then promises to take Lily to the pictures after he is been to work but later gets robbed. Lily over hears Martin talking to the rest of the family about it and decides to make her own movie, with the help of Hayley handing out the 'tickets'.
Jean then begins to take Hope, Lily and Arthur to church, hoping to convince Lily to get christened. However once Jean confronts Stacey about this, Stacey disagrees. Jean then decides to see Martin and Kush to see how they would feel about having the children christened. She asks Kush if he would like to see Arthur christened but Kush replies saying that he is a Muslim. Jean then asks Martin but he says that he isn't really religious and doesn't know how Stacey would feel about having Hope christened. Jean then mentions it to Stacey about having Lily christened and when Stacey asks Lily about this, she says she doesn't want to have one. Martin then begins to see how much a christening would mean to Jean after Jean confides in him that it would be the perfect idea for a big family gathering. Martin agrees as long as Jean manages to talk Stacey round. However Stacey tells her that she has three kids and she ain't treating one different from the rest butt Jean talks her round and eventually, Stacey agrees. Jean shows Stacey the dress she wore for her christening and she smiles. On the day of Hope's christening, Martin is drunk after a lads night out for his birthday with Kush and Robbie. The start of the day turns out to be a disaster when no body can find Hope's christening dress. Stacey picks Kat as hopes godmother and Martin picks Robbie as her godfather. Kat then goes a wall and tries to phone her husband Alfie so she can talk to her kids. Hayley then discovers that Hope's christening dress is inside the towel on her head and takes it to the church. With Kat being missing, Stacey needs to decide on a godmother for Hope and suggests Mo but Martin says her doesn't want Mo to be a godmother to his daughter and everybody laughs. Tiffany then says she will do it but her cousin Bex Fowler says she is to young. The vicar then says that these decisions can not be rushed just as Hayley walkes in the room. Hayley is then forces to get Hope changed into her christening dress and Jean talks her round into becoming Hope's godmother. Hope is about to be christened when Kat walkes in the room. Hayley then hands over Hope to Kat and walkes off. Jean then goes after her and Hayley confides in her that she is pregnant.
On 22 December 2017, executive consultant John Yorke announced a new member of the Slater family would be introduced into EastEnders among the returning Slaters, to "sort Stacey out" after her big 2018 storyline. Hayley's connection to the Slater family was not immediately revealed upon the character's debut, but it was announced that she would be involved in "a brand new mystery" for Martin. Duncan Lindsey, writing for the Metro, suggested that Hayley could be connected to the Slater family, either helping Stacey fight against her estranged husband Martin or a new family member. The reporter also suggested that Hayley could be acquainted with Martin's former stalker, Sarah Cairns (Alison Pargeter). It was reported that Hayley would not be friends with Martin, who will have to "watch his back" throughout his custody battle with Stacey. The character was revealed as Stacey's cousin in her third episode. Of her casting, Jarvis said that she is "really excited to join a team of such lovely, talented people and become part of such an iconic show" and loves being a part of the Slater family, commenting that it is "going to be so much fun and I cannot wait to see what’s in store for Hayley.”