His name is a tribute to Lou Beale.
Louie Beale was born after Lauren's waters broke when she came to see Jane about her dad being wrongfully arrested for Lucy's murder. His birth was very quick. He returned with Lauren to New Zealand to live with her, his dad and Uncle Steven. In May 2016, Lauren returns with Louie and Steven Beale. He then lives with his mum, uncle and grandad, Ian Beale. Lauren is excited when Louie says his first word: "mama". Steven gets him to say "dada" and records a video. Lauren sends it to Peter, which upsets Steven as he sees himself as Louie's father, but Lauren says Peter will always be Louie's father. Jane discovers Steven has been stealing money from the restaurant, he explains he borrowed it to pay Peter's debts as he is drinking heavily and getting into fights, and Lauren does not know the whole truth. When Lauren learns this, she is angry that he was not honest and considers visiting Peter. Steven says he wanted to protect her and Louie, and going to New Zealand out of guilt or pity will be a mistake, so she decides not to go.
Lauren meets Josh Hemmings and they share an attraction. Lauren insists on meeting up with him to see what happens. Josh suggests that Lauren apply for a job at the company he works for, Weyland & Co, where Max also works. Lauren is shocked that Josh is one of the interviewers as she thought he worked on the photocopier, so she leaves but Josh follows; she slaps him for lying but they kiss. Meanwhile, Steven is eager for a baby with Lauren but she would rather concentrate on her career, so Steven starts piercing holes in his condoms. Lauren reaches the final two for the job and Max asks Josh not to employ Lauren, and he makes sure someone else gets the job, however, Josh visits Lauren at home and offers her a different job, and he meets Steven and realises Lauren is in a relationship and has a child. Thanks to Abi, Steven becomes paranoid about Lauren and Josh's relationship and starts tracking Lauren's whereabouts via a mobile app. Lauren finds out she is pregnant, and books an appointment to discuss an abortion, soon after revealing her intentions to Abi, as she is not ready to have a second child. Max tells a disbelieving Lauren that Josh is engaged, then Josh admits he is getting married in November. Lauren surprises and annoys Abi by arranging a secret Father's Day visit from Oscar for Max, neglecting to tell Abi about it. However, this drives Abi to reveal the abortion to Steven, though he decides not to confront Lauren. Lauren tells Josh that she loves Steven but admits that there are no "fireworks", and tells Josh that she will not cheat on him, unaware that Steven has been spying on her with a secret camera. Unaware that Abi and Steven have embarked on an affair, Lauren realises she does not love Steven and plans on returning to New Zealand to make amends with Peter. However, Steven learns about her plans and lies to her that he has an inoperable brain tumour. Lauren is wracked with guilt and decides to remain in Walford. In another desperate attempt to keep her, Steven spontaneously proposes to her in the Queen Vic, which she accepts. Lauren then resigns from Weyland & Co and starts planning her and Steven's wedding, however, after a fire which he started at Ian's restaurant, he dies. Lauren is devastated. Abi tries to tell her that she is pregnant with Steven's baby but Lauren misinterprets it as gloating about her own abortion, so Abi says that she wishes Lauren died instead and that she never deserved Steven's love, causing Lauren to start drinking again. On the day of Steven's funeral, Lauren finds out he lied about having a brain tumour and destroys his wreaths. When she finds out that Steven has been cremated, she refuses to scatter his ashes. Abi decides to leave Walford to visit Tanya and when Lauren learns of this, she asks if she and Louie can join her. Abi agrees and they leave Walford together; unbeknownst to Lauren, Abi is secretly taking Steven's ashes with her.
Lauren returns and moves back in with Ian and asks Josh for her job back. Josh accepts and flirts with Lauren but she rejects him again, but after numerous attempts, Lauren eventually gives into temptation and kisses Josh. When Josh's former fiancee, Imogen, arrives unexpectedly at the office, she belittles Lauren and tells her that Josh dislikes children. To confirm this, Lauren asks Josh if he would like to spend time with her and Louie; he reluctantly accepts, but implies that they should go as a couple instead which displeases Lauren. Josh later tries to declare his love for he and asks why they cannot be together; she explains that they are different people and that she is a recovering alcoholic.
At Christmas, Louie's grandmother, Tanya Cross, returns to make Lauren, Abi and Louie come to live with her after being told by Jane that Max murderd Steven. After a confrontation of the rooftop of the Vic, Abi and Lauren fall off and are left unconscious on the floor. Lauren survives her injuries and is visited by Louie in hospital. Abi, who was pregnant at the time, has her baby delivered via c-section and later dies from her injuries after being left brain-stem dead, so her family turn her machine off. Louie's new cousin, named Abigal Branning Jnr is taken to live with his grandad, Max Branning.
On the day of Abi's funeral, Lauren tells Whitney about her planned move to Scotland with Josh and Whitney asks her to be sure that she actually loves him or if she is only with him because he is good with Louie. After the service, she sees Max going into the chapel and tells him that she needs to leave, before hugging him and crying. Lauren then takes Louie from Josh and walks away without him. Both her and Louie leave Walford.