Jack Osborne is a fictional character from the British Channel 4 soap opera Hollyoaks, played by Jimmy McKenna. The character debuted on-screen during the episode broadcast on 18 November 1996 and is the second longest featured character in the show. He was introduced as part of the Osborne family, which also consisted of Jack's wife Celia (Carol Noakes) and their children Darren (Adam Booth/Ashley Taylor Dawson) and Ruth (Terri Dwyer). His storylines include an affair with Dawn Cunningham (Lisa Williamson), four marriages and faking his own death in an insurance scam. For numerous years, Jack's role in the show is the landlord of the pub, The Dog in the Pond. During Hollyoaks' 30th anniversary the show aired a special crossover with former soap Brookside, McKenna along with most of the then current Hollyoaks cast appeared in the episode.

McKenna is the show's second longest serving cast member having appeared consecutively since 1996. A reporter from Daily Record wrote that Jack had been "drafted in to quicken the pace" of the soap. McKenna began filming after original cast member, Nick Pickard who plays Tony Hutchinson. In an interview for E4.com, Pickard stated that he joined the cast "in October and he [McKenna] came in at Christmas"; this equated to McKenna joining "about 20 or 30 episodes" later.

A writer from the official Hollyoaks website described Jack as "no nonsense but a good sport." Writers later created a relationship storyline between Jack and Frankie Dean (Helen Pearson). In 2007, the show's executive producer Bryan Kirkwood adored "I love Jack and Frankie – they're essentially the heart of the show".

In 2003, Jack becomes responsible for teenager Norman Sankofa (Jamie Luke), who moves into his flat as a lodger. Writers reintroduced Jack's son, Darren Osborne (Ashley Taylor Dawson), who then has to share a room with Norman. Dawson told Joanne Tebbutt All About Soap that Darren "hates" the situation and feels that Norman is preventing him from having Jack's full attention. Dawson believed that Darren "resents" Norman and begins feuding with him. Darren's behaviour causes Jack to react angrily towards Darren. Dawson revealed that Darren "uses emotional blackmail" against Jack which causes a confrontation. Darren stays out all night and worries Jack, which makes him reconsider and tries to bond with his son. Jack's attempts to be a better father are disastrous. Jack introduces Darren to his friends, but they tell Darren that previously believed Jack did not have a son. Dawson described Darren as "understandably upset" and "feels that once again his dad has let him down." Dawson believed that Darren secretly "wants to get on better with his dad" but is "really bitter" and "insecure". Darren ultimately feels that Jack has never allowed him to feel welcome where ever they have lived. Dawson added that Jack and Darren have "an interesting relationship" which meant they would "continue to clash".

The Osbornes suffered financial crisis when Darren's gambling addiction grew out of control. It was announced that Jack would fake his own death to claim on the life insurance. Darren found Jack about to commit suicide, before finding the body of Eamon Fisher (Derek Halligan). Darren and Jack decide to fake Jack's death, which Jack reluctantly agreed to. A Hollyoaks publicist told Kris Green from Digital Spy saying "Jack's at an all-time low and the finding of a dead body is too good an opportunity for him and Darren to pass up. They swap the dead man's identity with Jack's, forcing Jack to slope off into the night." They added that Darren receives the "formidable task" of telling Frankie that Jack is dead and a "tangled web of lies" develops. Eamon turns out to be the father of Kris Fisher (Gerard McCarthy) and Malachy Fisher (Glen Wallace), which puts Darren in an "extremely tricky position" as they continue to search for their father. They concluded that "It's only when Jack turns up at his own funeral that Darren realises that the situation has truly spiralled out of control".

Kirkwood revealed his plans to feature Jack and Frankie at "the centre of the programme" as they embark on becoming foster parents. Kirkwood revealed the introduction of Barry "Newt" Newton (Nico Mirallegro), who he described as a "very important character", who would become the Osborne's first foster child. Jack was featured in a story which included an under water stunt. When Jack's foster son, Newt attempts to commit suicide by drowning, Jack saves Newt's life. Executive producer Lucy Allan described it as one of her favourite scenes and branded him as "Jack the hero!"

In 2023, Jack was romantically paired with Pearl Anderson (Dawn Hope). In the storyline, Pearl helps Jack host the Earl Of Dee survival workshop. Hope revealed that the romance begins from a dare, as teenagers Lucas Hay (Oscar Curtis) and Dillon Ray (Nathaniel Dass), who want to win prizes from the workshop, then play cupid and tell Pearl that Jack has been speaking so highly of her, suggesting that she ask him out. Pearl appears to fall for their trick and asks Jack out, although the pair have already realised that they have been played. Hope believed that this was the "beauty" in the beginning of the friendship and added that Pearl was previously not aware and missed all of the hints when Jack "kept coming" into her shop to buy milk. Hope enjoyed working with McKenna, calling him "awesome" and a "brilliant actor". The actors have mutual friends going back 40 years, and Hope believed that her scenes with McKenna were similar to improv. She added, "It's been so special to put these two characters together!"

Jack and Pearl spend more time together overseeing the Earl of Dee Awards and they then attend the opening of Tony Hutchinson's (Nick Pickard) new restaurant. Jack is surprised but happy to see that Pearl has arrived and whilst there, they grow close and Pearl sees another side of him when they dance together, and they ultimately kiss. Hope explained that Jack – in his "beautiful chivalry" – almost accidentally halts the romance when he tells someone that he and Pearl are just friends, which Hope revealed creates a bit of awkwardness and "wrong-foots" Pearl as she is expecting him to call her his new "lady love". Hope revealed that this makes Pearl realise that she needs to make a declaration, so she "has to lead him into it a bit with the kiss – although Jack goes with it, and is very happy!" Hope called the scene where Jack and Pearl kiss in the middle of the pub, with the crowd around them cheering at this, a "beautiful moment". Discussing the romance, Hope told Inside Soap, "Being mature, you go through processes in life of how you date. How you want to be treated grows more prevalent – and chivalry goes a long way when you're over a certain age as a woman. So when chivalry turns up in the shape of Jack, it kind of wrong foots Pearl and she goes, oh, that's nice!" Hope explained that now that Jack and Pearl are together, they need to figure out what that looks like. Months later, Pearl organises a surprise birthday party for Jack with Darren, which he appreciates. Pearl and Tony also cover for Darren when a debt collector comes looking for him, but Darren pushes them away as he does not want to open up about the extent of his problems and debt. In July 2025, Pearl briefly breaks up with Jack following various family troubles, which really upsets him.