Born Sarah Louise Tilsley on 2nd February 1987, Sarah and her older brother Nick were adopted by Martin Platt when he married Gail in 1991. Martin was the only father Sarah knew as she was two years old when Brian Tilsley was stabbed to death. David Platt, youngest of the clan, was Sarah's half-brother.
Sarah was catapulted into adulthood when she had Bethany at thirteen. The father was Neil Fearns, a schoolmate of Sarah's who had no involvement in Bethany's upbringing. Sarah juggled her responsibilities at home and school for a few years until she left to live with boyfriend Todd Grimshaw in 2003. Todd rushed Sarah into getting engaged and pregnant before confessing that he was gay and had been having an affair with nurse Karl Foster. The stress caused Sarah to go into premature labour and their son Billy died after three days.
In 2007, Sarah married Todd's older brother Jason and planned a fresh start in Milan. However, after discovering that Sarah had plotted to steal the opportunity from David to work in the fashion industry for their uncle Stephen Reid, a sickened Jason let Sarah go without him. As Bethany grew up and became more of a handful, Sarah had to return to Weatherfield and was sacked in 2015 for losing focus on her work priorities.
Sarah's life since then has seen her work as a barmaid at the Rovers Return and later PA at Underworld, her current job. After getting divorced in 2010, she was involved with Callum Logan, who fathered her third child, Harry. Sarah finished with Callum when she found out that he'd used Bethany as a drug mule. Callum was then killed by David's wife Kylie when he violently assaulted Sarah. In the months that followed, Sarah was treated for postnatal psychosis when she became convinced that Callum was still alive and barricaded herself and Harry inside 8 Coronation Street.
1987-1999: Early years
Sarah was born three weeks prematurely. Her dad Brian Tilsley initially rejected Sarah because of Gail's affair with his cousin Ian Latimer. However, a blood test proved that Sarah was Brian’s daughter. Gail was planning to keep the paternity a secret and raise Sarah herself, but told Brian after Gail's mother Audrey Roberts accidentally revealed it during a heated argument with him. Brian didn't believe it at first but eventually came to understand and accept Sarah as one of his own and it took some time for him to bond with her.
Brian was murdered by a group of thugs shortly after Sarah's second birthday. Gail's second husband Martin Platt adopted Sarah and her brother Nicky and raised them as his own, despite Gail's former mother in law, Ivy Brennan, trying to make it difficult for Martin to adopt.
In March 1994, Sarah's appendix ruptured and she had an emergency operation which she soon recovered from.
1999-2000: Sarah Louise's teenage pregnancy
In her early teenage years, Sarah was a fussy eater because she thought she was fat. Gail became exasperated and made Sarah eat her meal in front of her, saying that they would do it that way every morning until she changed her behaviour. After hearing her being sick in the bathroom, Gail decided to take her to the doctor under the impression that she was developing an eating disorder. Sarah was examined by Dr Wilson who told them that Sarah was five months pregnant, meaning it was also too late for an abortion. This news also meant that Martin's plans to leave Gail for nurse Rebecca Hopkins, whom he was having an affair with at the time, were ruined when he realised that he had to stay and support his family.
Sarah didn't want to tell anyone who the baby's father was. When Sarah told best friend Candice Stowe of her pregnancy, Candice worked out for herself that Neil Fearns was the father. Some months later, Gail and Martin were shocked when they saw Neil in the schoolyard of Weatherfield Comprehensive as they both thought it was someone older who had taken advantage of Sarah.
Gail and Martin both kept Sarah's pregnancy a secret until they decided what to do. Gail was desperate to give Sarah her childhood back and she suggested taking Sarah to Canada to stay with her half-brother Stephen Reid. Her plan was that once Sarah had the baby, they would return and pass the baby off as Gail and Martin's. However, news of Sarah's pregnancy had already spread around the school and closer to home, believing Gail to be pregnant, the residents of the street found out about it when Audrey accidentally told them who the real expectant mother was. Blanche Hunt and Candice's mother, Marion Stowe, disapproved of Sarah after discovering she was pregnant and often delivered hurtful remarks at her.
Sarah was disappointed when she couldn't perform in the school production of Grease, but was instead given the job of stage manager. Hayley Cropper helped cheer up Sarah and offered to help her with the costumes.
In June 2000, Sarah gave birth to her daughter Bethany. Out of her depth and being alone in Weatherfield General, she found it hard when the baby cried and she wasn’t able to settle her. Neighbour Alison Webster, who just lost her own baby, agreed to look after Sarah's and when no one was looking, Alison ran off with baby Bethany. Sarah blamed herself for her daughter's kidnapping and she confided in Gail that she was thinking about what the residents would think about her being a teen mum. Kevin Webster made Alison see sense and return Sarah's baby before she was run over by a lorry.
Sarah originally called the baby Britney after singer Britney Spears, but Audrey wasn't keen on the name. As a compromise, Sarah settled for Bethany as a the baby’s first name with Britney as her middle name.
Sarah had Bethany christened in August 2000 with Candice and Hayley as her godmothers and Roy Cropper her godfather when David did a runner from the church. However, the christening party was ruined when Marion turned up at 8 Coronation Street to collect Candice and then she made a scene while David was brought home in a police cab after he was caught shoplifting.
2001-2003: Gary Adams and Aidan Critchley
Since she had a baby in her early teens, it was difficult for Sarah to date other boys. She dumped her first boyfriend, Glen Middleham, in January 2001 after he falsely said that he and Sarah slept together.
In 2001, Sarah went on internet chat rooms and met a guy named Gary Adams online. She went to his house but was shocked and frightened to discover that Gary was a actually a man in his early thirties. She managed to call Candice to pick her up but Gary locked her in his bedroom. Candice and Todd Grimshaw managed to break into his house to save Sarah but Todd was injured after Gary pushed him over his fireplace. Gail and Dennis Stringer rushed to Sarah's aid while Dennis gave Gary a good beating. Gary was later released on bail.
Whilst new stepfather Richard Hillman and Gail were away, Sarah and Candice had a row over who was seeing Ade. He asked both Sarah and Candice to meet him at 11.00pm and he turned up in Ken Barlow's stolen car. Sarah backed out and the next day, she saw Candice and Ade kissing. Candice made Sarah jealous and she made out that she and Ade slept together. Sarah went joyriding with Ade in Ken's car. Sarah became panicked when Aidan started going faster and pleaded with him to slow down and take her home. However, the car clipped the kerb and the car turned onto its roof. Aidan escaped from the car and fled after being unable to tell if Sarah was dead or alive. Police officer Emma Watts told the Hillmans what had happened and that Sarah was critically ill in hospital. They rushed there to be told that Sarah had to undergo emergency surgery to prevent a blood clot and that brain damage couldn't be ruled out.
Teenage neighbour Todd, who fancied Sarah himself, visited her in hospital and was there when her eyes opened. As she was recovering, she realised that Todd missed his open day at Oxford University for her. She started remembering what happened in the crash and dumped Ade when she realised that he had left her in the wreckage. As revenge, Richard framed Aidan for the murder of Maxine Peacock and the attempted murder of Emily Bishop as revenge for nearly killing Sarah. Sarah was shocked when she discovered Richard killed Maxine and she demanded answers from Gail.
In September 2003, Sarah discovered that Neil Fearns had died in a car crash. Sarah took Bethany to Neil's funeral, where she made friends with Neil's mother, Brenda. Brenda became close to her granddaughter but Sarah banned her from seeing Bethany after she discovered that she has been taking her to Neil's grave and due to her mental state caused by the loss of her son, Brenda kidnapped Bethany, not believing that Sarah was looking after her properly.
Brenda thought the only thing she could do was join Neil in heaven, so she decided to throw herself and Bethany off the tower of St. Saviour's Church. Emily managed to talk Brenda down and Bethany was reunited with Sarah.
2003-2004: Relationship with Todd Grimshaw
Shortly after Sarah left school, she moved in with Todd and got a job at Roy's Rolls. This built up a difficult relationship between Gail and Sarah, especially when Gail tried to call social services. This led to Sarah angrily confronting her, telling her to stay away from her and Bethany.
Todd loved Bethany, but wanted Sarah and him to have a child of their own. Gail wasn't pleased to learn that Sarah was pregnant again at the age of 16. Sarah was thinking about having an abortion but Todd convinced her to go ahead. Sarah was left devastated when she discovered that Todd was gay and he'd been having an affair with Karl Foster. She dumped him and suffered a placental aruption shortly afterwards. Sarah and Todd's son, Billy, was born prematurely and only lived for three days.
Sarah didn't want Todd at Billy's funeral, but grief-stricken he showed up and told Sarah he wasn't there for Billy when he was alive and needed to be there now. Sarah let him scatter some earth over the casket and say a few words, but she broke down watching him.
2005-2015: Jason Grimshaw and Milan
After a short relationship with Scooter Makuna in 2005, Sarah became interested in Todd's brother, Jason. Jason began an affair with Sarah, even though he was with Violet Wilson, but he eventually left Violet for Sarah. In March 2006, they became engaged. They attempted to marry later that year, but Jason got cold feet and ran away. After the incident, the pair made up and planned a second wedding.
In September 2007, David hid ecstasy tablets in Bethany's doll. Bethany took one when David was meant to be babysitting but he kept quiet about it when Sarah came home. A few hours later, Bethany started fitting and an ambulance was called. When Bethany was in critical condition in hospital, Sarah became frantic but David still refused to admit what was causing it. When David learned that Bethany was facing death, he confessed what had happened to a furious Sarah. After the incident, Sarah refused to speak to David or live with him, even banning him from her wedding. Bethany eventually recovered after a few days and went home.
In October, Sarah and Jason married, although the day was ruined when David faked a suicide attempt. This caused a rift between Gail and Sarah since she had thrown away David's suicide note knowing it was a sick stunt.
David was offered a job in Milan by his and Sarah's uncle, Stephen Reid. Sarah got revenge on David by planting ecstasy in his drawer, and she was given the job instead.
In December 2007, Sarah left for Milan with Bethany and Jason. Jason changed his mind and refused to go when he found out about Sarah's revenge on David. Sarah and Bethany went without Jason and the couple split up. Sarah and Bethany were visited by Gail in July 2008 and again in June 2009 with Audrey. Sarah officially divorced from Jason in 2010.
2015: Return and Callum Logan
After fourteen-year-old Bethany came back to Weatherfield alone without Sarah's knowledge, Sarah was forced to return to Weatherfield in order to bring her back. Sarah found that Bethany had left Milan because she was unhappy there, and that she thought her mother was more interested in her work than in her. Before Sarah and Bethany had chance to return to Italy, Bethany successfully attempted to mess this up, and after losing focus on her work, Sarah was sacked.
Sarah moved back to Weatherfield and got a job at Rovers Return Inn while Bethany started attending Weatherfield High. Sarah became involved with Callum Logan who was in the middle of a custody battle with David over Max Turner. Callum was a known violent drug dealer, but Sarah ignored all the warnings about him when she was drawn in by his charms. They secretly began dating but when David found out it caused havoc and he kicked Sarah and Bethany out of No.8.
When Sarah and Callum were dating, Bethany also became interested in him. He manipulated Bethany into dealing drugs for him and took video footage of it. Sarah found out about Callum's true nature when he left a loaded gun in Max's room and he blackmailed her with the videos of Bethany. Eventually, Sarah told her family and the police about the incident but no evidence was found.
Callum and two of his thugs beat up Jason when he stood up for Sarah. Max witnessed the incident and was taken to the police station to make a statement. Callum spiked Sarah's drink in the pub making her fall asleep in her house. He then video-called Bethany and showed her a video of the drugged Sarah, forcing her to give him an alibi and tell the police and say she was with him and Gemma Winter on the day that Jason was attacked.
On the day of Lily Platt's second birthday, the family found out that Bethany had given Callum a false alibi. However, Bethany retracted her statement after Callum started threatening Audrey. Max no longer wanted Callum in his life after his attack on Jason, so Callum told David and wife Kylie Platt that he'd give up his custody rights of Max to them if they gave him £2,000. Kylie discovered that he wanted the money because he was in deep debt to a drug dealer named Denton. Sarah tricked Callum into going round to No.8 (pretending to be Kylie), where she attempted to secretly record him confess using her phone. Callum discovered what she was doing and he attacked her. Kylie bludgeoned him over the head when she saw what was happening. Callum died instantly.
David was called to help decide what to do next. He planned on moving the body into the canal and in the meantime, it was hidden under a drain in the garage. Before they had a chance to move the body, the drain cover was concreted over and the garage was converted into Gail's "granny annex".
2015-2016: New baby and mental health struggles
Sarah was distraught over Callum's death and was on the verge of a breakdown. When she confided in vicar Billy Mayhew for comfort, David, afraid that his sister would accidentally confess, forced her to return to Milan with Bethany for a few weeks. She did so and returned a month later, trying to get back to normal. David was not convinced and believed she could snap at any moment. The two had a feud at Victoria Court and Sarah was accidentally run over by Tim Metcalfe.
While recovering in the hospital after the accident, Sarah discovered she was four months pregnant with Callum's baby. She decided to have an abortion thinking that it would erase Callum from her mind but Todd reminded Sarah of how she felt after losing Billy while Kylie stopped her from undergoing the procedure after telling Sarah about her love for Max. David was furious when he found out, and Bethany angrily confronted Sarah at Nick's Bistro and told Audrey and Gail the news.
Sarah went into labour five weeks early. Despite her fear that the birth would go wrong like with Billy, she successfully gave birth to her second son, Harry Platt, in March 2016. Not long after his birth, Sarah became paranoid that Harry could feel Callum's presence.
In May 2016, Callum's body was found under the Platts' house after Tyrone Dobbs crashed his pick-up truck into Gail's annex. After these events, Sarah's mental health took a turn for the worse and she became increasingly convinced that Callum was still alive and after her. Sarah was not implicated for her part in Callum's murder because Todd had pinned the crime on the recently deceased Tony Stewart so that Sarah would not risk facing prison. However, Sarah was so frightened that Callum would find her that she changed the locks on No.8 and barricaded herself inside with Harry. She was eventually taken to stay in Weatherfield General's psychiatric ward for a number of weeks where she was diagnosed with postnatal psychosis.
In July, while Sarah was still in hospital, Kylie was murdered by fifteen-year-old thug Clayton Hibbs. David and Bethany broke the news to Sarah a few days later. Soon afterwards, Sarah had recovered well enough to go home. In October, Sarah, Gail and Nick learned that David was planning to kill himself and Clayton by driving a petrol-doused car into a police van that Clayton would be transported in on the day of the trial. Out of desperation, the trio locked David in the cellar of the bistro, planning on releasing him when the trial was over. David escaped when he tricked Gail into thinking he had killed himself, and got into his car. He ignored his family's pleas to stop and drove off, but when he spotted Lily in the road, he swerved and crashed, trapping both Lily and Gary Windass. Sarah helped to rescue Lily.
- Sarah was played by twins Leah and Lynsay King as an infant. Leah died of cot death at a few months old but Lynsay continued to play the role until October 1999 when she was replaced with Tina O'Brien.
- In April 2007, it was announced that Tina O'Brien would be leaving Coronation Street to pursue other projects. The character departed in December 2007. In August 2014, it was revealed that Tina O'Brien would reprise her role as Sarah and she returned onscreen in March 2015.
- Sarah's teenage pregnancy storyline was praised by both Coronation Street viewers and the UK Government at the time, and even won the award for best storyline of 2000 at the British soap awards.
- She is the first Coronation Street character to become a teenage parent. However, this does not include older characters who gave birth off-screen prior to their first appearance; like her grandmother Audrey, for example.