Zack attends
Gavin Sullivan's (
Paul Nicholas) cremation and at the wake, he raises a scathing toast to Gavin and is chased by his cousins. Zack hides out in
Kathy Beale (
Gillian Taylforth) and
Sharon Watts' (
Letitia Dean) car until the coast is clear and when Sharon asks about his identity, he tells her that Gavin was his father. Zack tells Sharon about a time when he baked Gavin some cakes at school but he was unappreciative and stubbed out his cigarette in one, leaving him humiliated. As he goes to leave, Sharon tells him that Dennis died the previous year and asks Zack to stay, to which he initially refuses, although returns later with food and wine for them both. Zack finds himself on the wrong side of
Martin Fowler (
James Bye), who punches him when he believes that he has been sleeping with his wife
Ruby Allen (
Louisa Lytton). He later becomes friends with Martin and starts working as a barman at
The Queen Victoria public house. Zack starts dating
Nancy Carter (
Maddy Hill) and also flirts with her half-sister
Frankie Lewis (
Rose Ayling-Ellis). He gives Frankie driving lessons and in one of the lessons, he stops off at the Queen Vic to have a drink and continues. Zack resumes flirting with Frankie and winds her up, causing her to take her eyes off the road. They are involved in a
hit-and-run accident, in which Nancy gets hit by the car. Zack persuades Frankie to cover up the accident but it proves too daunting for her and she confesses to Nancy's father
Mick (
Danny Dyer). Mick agrees to hide it from Nancy and warns Zack away. However he cannot resist and continues to see Nancy, keeping it a secret from Mick. Whilst upstairs in The Queen Vic, Nancy's mother
Linda (
Kellie Bright) is threatened by burglars who attempt to steal money, but Zack stands up to them and they leave. Mick discovers that Zack is sleeping with Nancy, but he ignores Mick's threats to leave her. Zack then admits the truth to Nancy and she subsequently ends their relationship. After this, Zack sleeps with
Janine Butcher (
Charlie Brooks) but realises he loves Nancy and attempts to make amends. When
Alyssa is left on Sharon's doorstep, both Zack and Martin believe that they could be her father, however when Alyssa's mother
Jada Lennox (Kelsey Calladine-Smith) arrives in Walford, she reveals that Zack's late nephew, Dennis, is Alyssa's father. Jada moves in with Sharon and Zack soon realises that Sharon and her ex-husband
Phil Mitchell (
Steve McFadden) are planning on battling Jada for custody of Alyssa. He tells Jada and she flees with Alyssa. When Sharon finds out that Zack told Jada about her intentions, she evicts him and he is left homeless. He manages to find Jada and convinces her to return with Alyssa, and they all move into 43 Albert Square with Sharon. Zack builds his relationship with Nancy, and she supports him when he has the opportunity to participate in a cooking competition, letting him use The Queen Vic's kitchen for practice. They grow closer and resume their relationship. He supports Nancy when she learns that her aunt
Tina Carter (
Luisa Bradshaw-White) – who is thought to have been on the run – has been murdered by
Gray Atkins (
Toby-Alexander Smith). Zack and Nancy decide to open a restaurant together, and they meet with Melissa (Hannah Bennett-Fox), who they believe is an investor. Unbeknownst to the both of them, Melissa is working with Janine to swindle the pair, so she can use the money to pay Linda into leaving Walford. Melissa tricks Nancy into transferring money into her account, and they become suspicious when they do not hear back from the investor; they later discover that Nancy has been conned. Zack bonds with Jada and she tries to kiss him, but Zack rebuffs her advances. She lies to Sharon that Zack tried to kiss her, and Sharon threatens to throw Zack out in order for Jada to admit the truth. Jada later admits to Sharon that she lied. During a stormy time with Nancy, Zack drowns his sorrows at the club, where he sleeps with
Sam Mitchell (
Kim Medcalf). Nancy finds out and after much consideration, she decides to make a fresh start by leaving Walford without Zack, thus ending their relationship. Soon after, Zack and Sam begin a fling and when Sam's ex-boyfriend Don (
Nick Nevern) arrives in Walford, she claims that she is pregnant with Zack's child. Sam later reveals that she lied to drive Don away, and when she asks Zack to begin a serious relationship, he turns her down. Zack becomes close to
Whitney Dean (
Shona McGarty) and they have a one-night stand. Zack is surprised when Whitney reveals that she is pregnant. He later takes on legal responsibility for his nephew
Albie Watts (Arthur Gentleman) after Sharon cannot trust
Keanu Taylor (
Danny Walters) to raise Albie alone after a very public bust-up with
Peter Beale (
Thomas Law). Whitney and Zack foster a young boy named Ashton over Christmas 2023 and struggle when he is moved away. Not long after, Whitney discovers that she is pregnant again. Whitney and Zack visit her adoptive mother
Bianca Jackson (
Patsy Palmer) in Milton Keynes. While there, Whitney bonds with twelve-year-old
Britney Wainwright (
Lola Campbell) and is disgusted to find Britney's mother
Keeley Wainwright (Kirsty J Curtis) is a drug addict. Whitney angrily confronts Keeley and is hit by an oncoming car; however, Whitney and the baby are unharmed. Whitney is eager to foster Britney, against Zack's wishes. Whitney pays Keeley several thousand pounds to take care of Britney herself, but keeps this from Zack. She initially tells him that she fostered her legally, and when Zack finds out, Whitney fiercely tells him that she will always put Britney over Zack. Zack then sleeps with Whitney's best friend
Lauren Branning (
Jacqueline Jossa). Whitney proposes to him at the Queen Vic and Zack accepts. Bianca returns to Walford and finds out that Zack has slept with Lauren and pressures him to tell the truth but he is unable to go through with it. On Whitney's hen night, Lauren and Whitney are locked in a van, and she nearly tells Whitney herself, but Whitney then goes into labour. Bianca rescues the pair, and Whitney gives birth to
Dolly Dean-Hudson, but at the hospital, Britney overhears Zack and Lauren talking about their one-night stand. During their wedding ceremony, Britney exposes Zack and Lauren's dalliance. Whitney calls off their wedding and refuses to reconcile with Zack. She then realises that she has wasted her whole life relying on men and plans to make a fresh start as a single mum to Britney and Dolly by moving to
Wakefield. When Zack asks Whitney if he can see Dolly again, she promises to allow this, assuring him that he will be a great father, and allows him to say goodbye to Dolly. Zack mentors teenagers in boxing at the Boxing Den. He later discovers that
Denzel Danes (
Jaden Ladega) has been taking steroids and has provided them to Ravi's son
Davinder "Nugget" Gulati (
Juhaim Rasul Choudhury), who overdoses. Zack encourages Denzel to confess. Zack moves in with Martin and temporarily fosters
Tommy Moon (
Sonny Kendall). When Martin
is killed in the Queen Vic Explosion, Zack supports a grieving Sharon whilst dealing with his grief. He agrees to help conceal Sharon's one-night stand with
Grant Mitchell (
Ross Kemp) from her current partner and Grant's cousin,
Teddy Mitchell (
Roland Manookian), but they are overheard by Teddy's son,
Barney (
Lewis Bridgeman). Zack confronts Barney to try and keep him silent but Barney collapses from wounds he sustained during the explosion; when the paramedics arrive, Zack realises that he is Barney's biological father due to their matching
blood types and his previous affair with Teddy's then-wife,
Nicola Mitchell (
Laura Doddington). Nicola confirms this and has Zack beaten up to prevent him from revealing the truth. Zack tells Sharon about Barney's paternity - Nicola and Sharon agree to keep each other's secrets, but Barney reveals Sharon's infidelity to Teddy, resulting in a confrontation between the couple; Zack steps in to defend Sharon but is violently beaten by Teddy. Afterwards, Nicola warns Zack and Sharon not to inform Teddy of Barney's parentage by alleging that Teddy murdered their son
Harry's (
Elijah Holloway) girlfriend Shireen Bashar; it soon transpires that Nicola is the true killer. Zack still attempts to bond with Barney by helping him at the gym; Nicola responds by sabotaging these attempts and firing Zack from the wine bar. Shireen's body is soon discovered, and Teddy and Nicola successfully frame
Benji Haynes (
Carl Prekopp) for the crime. Zack confronts Nicola, who confesses that she murdered Shireen - and threatens to do the same to Whitney and Zack. Horrified, Zack arranges for Whitney and Dolly to go into hiding with him in
Inverness but soon concludes that Barney isn't safe with the Mitchells, and makes plans to flee Walford with him. Zack reports Nicola to the police for Shireen's murder - she is soon released without charge, and informs Harry of her guilt and Barney's parentage in the hopes that Harry can persuade Barney to follow him. Harry refuses to allow this to happen and attacks Zack before driving him into the countryside in Teddy's car; he is stopped by Teddy, his half-brother
Billy Mitchell (
Perry Fenwick), Billy's wife
Honey Mitchell (
Emma Barton) and
Nigel Bates (
Paul Bradley). Teddy places an unconscious Zack in the front seat of the car and begins to drive back to Walford; however, Zack regains consciousness and attempts to grab the wheel, resulting in the car driving off a bridge and crashing into a lake. Teddy escapes the wreckage, but Zack is nowhere to be found, leading the group to believe he has
drowned. Zack ultimately survives and returns to Walford that night and discovers Barney now knows the truth - having been told by Sharon's half-sister
Vicki Fowler (
Alice Haig). Zack attempts to convince Barney to flee Walford with him, explaining Nicola's crimes, but is ultimately devastated when Barney decides to remain with the Mitchells. However, Barney informs Zack that he is open to forming a relationship. Zack turns to Lauren, and they kiss, which almost ruins her relationship with
Peter Beale. ==Reception==