Introduction and characterisation Jack arrives in Erinsborough with no family ties and a 'mysterious past' of which Paige helps him discover. Determined to find out his past, Paige becomes curious in Jack and decides to visit him in hospital, later becoming fascinated by him. With his details unknown, he is given the name
John Doe. When talking about John's future identity, Morley described it as "completely off the scales". He also guaranteed that nobody would pick what his character turns out to be. Morley said "It's a good little journey and the audience is going to love it." He later remembers that he is a
Catholic Priest and goes to the police station to inform them of his past and his true identity is confirmed as Father Jack Callahan. After Mandy kisses John, Paige is forced to accept that she has lost him for good. After Jack dreams of a kiss with Paige, he goes to
Father Guidotti (
John Orcsik), the local priest for advice. He later
prays and asks God for a sign. After Father Guidotti dies, Jack sees this as the sign he asked for from God, with Jack feeling his death was down to God allowing him to continue his work in Erinsborough. Paige later goes to confession and tells Jack of her recent hookups, to show that she has moved on from him. Daniel Kilkelly from
Digital Spy commented on Paige's visit to confession saying, "Jack Callahan is probably used to awkward confessional visits every now and again, but this one really takes the biscuit". This leaves them no longer on speaking terms, but after Paige goes on a hot air balloon trip that ends up crashing, Jack comes to find Paige and the pair sleep together. However, an old friend of Jack's,
Simone Bader (Kahli Williams), turns up in Erinsborough and after finding out Jack had slept with Paige, she questions if she is worth leaving the priesthood over. Paige finds out she is pregnant with Jack's baby, but decides against telling him. When Jack comes to Paige's rescue after she is involved in a car accident, she reveals to Jack that the baby is his. Paige considers leaving Erinsborough to move to Queensland along with her parents, taking the baby away and leaving Jack behind, but ultimately decides to stay. Paige goes back to where the baby is conceived and goes into labour and gives birth to a son,
Gabriel Smith (Kian Bafekrpour). Jack along with
Karl Kennedy (
Alan Fletcher) come to Paige's rescue and takes her and the baby to hospital. The pair later reunite and sleep together, betraying both their partners. Morley commented in an interview with
Radio Times, "At that moment and with Gabe in front of them, everything felt so right and they went for it. That gave Jack hope but afterwards Paige wants to bury it and forget it happened. This hurts Jack who wants to tell Steph, even though he knows she'd be upset, but Paige is not of the same mindset and regrets it."
Relationship with Stephanie Scully After Steph helps Jack look after his son, Gabe, they develop feelings for one another and have sex. Continuing their relationship however, Jack realises he is not Steph's priority when 'having a relationship' didn't feature on a list of what she wants to do in her life. After Steph returns from a Christmas break with her mother, Steph expects to see Jack waiting for her when she returns, however instead he is with Paige. When he eventually sees Steph, he cancels his lunch with her to spend time with Gabe and Paige, but Steph insists she comes along too. She later becomes irritated as Jack's attention is focused on Gabe during the outing. However, Steph talks to her friend
Toadfish Rebecchi (
Ryan Moloney) about her concerns, feeling the age difference between herself and Jack may be too big. Toadie later gives Jack advice on how he can keep Steph happy in their relationship. Kilkelly also reported that Steph would seek revenge when she finds out about the affair with her ransacking Jack's room at the backpackers in a fit of anger but later confesses to the police of her actions. This brings repercussions for Steph as her planned trip for visiting her son in Fiji is ruined as her overseas visa is revoked due to the criminal charges for the damage.
Rivalry with Mark Brennan On 13 November 2017, it was reported by Kilkelly (
Digital Spy) that Jack would "drive" Paige and Mark's relationship apart when he discovers that the pair are arguing. Jack challenges Mark about his behaviour, but without an explanation Mark is forced to steer clear from Paige and his baby. Later, in December 2017,
Digital Spy reported that Jack would get into a "violent" fight with Mark in the new 2018 season. After Gabe is kidnapped, with Paige dating Mark, he becomes involved and tensions rise between the pair. With
Elly Conway (
Jodi Anasta) and
Amy Williams (
Zoe Cramond) determined to get Jack and Mark on better terms, they decide to get them together with a game of
Croquet. But a feud starts to arise and meets its climax when the pair have a "full-blown brawl" in public. Sophie Dainty from
Digital Spy described the scenes as "explosive". During the fight, Jack's anger causes him to tell Mark how he really feels and blames Mark for his son's recent abduction. After Paige discusses the "awkwardness", "occasional violence" and how Jack feels threatened by Mark as he feels he is "muscling in on his family", Paige goes to see Jack. When Paige turns up, old feelings arise from their previous relationship and Jack ends up sleeping with Paige.
Departure and return On 19 March 2018, it was confirmed that Morley would be leaving
Neighbours alongside Valance. After seeing how much Mark is struggling with their relationship, Paige and Jack decide to leave Erinsborough for a fresh start in Queensland with their son. Jack returns alongside Paige on 26 February 2020. ==Storylines==