Jez was the original licensee of The Jockey. An open lesbian and all round 'no nonsense' kind of woman, Jez showed a distinct distrust of men, especially her regular customer Frank Gallagher. Karen Jackson flirted her way into a job at The Jockey as well as taking a room in the flat above the bar. This lead to Jez developing feelings for Karen, unaware that she was in fact heterosexual. She even went so far as to chastise any male customers who flirted with Karen.
When Karen first got her job at the Jockey, she was working alongside Kevin Ball, his girlfriend Veronica Fisher became very jealous of both Karen and Kev's friendship and the fact Karen was getting more tips. Veronica attacked Karen on multiple occasions, leading to Jez barring her and though Veronica attempted to still frequent the Jockey in disguise she couldn't help but start another fight with Karen and was thrown out again. Eventually Karen and Veronica bonded over a drink and Karen agreed to share all tips 50/50 and help get Veronica's ban lifted. They hatched a plan for Jez to walk in on them kissing passionately, Veronica pretended to beg Jez not to tell Kev and having sympathy with her "lesbian tendancies" Jez lifted her ban but warned her to stay away from Karen.
Karen continued to hide the truth about her sexuality from Jez for quite some time, sneaking any boyfriend into the pub itself at night to have sex. Things took a turn however when Karen's mother Sheila fell for the lie that Karen was a lesbian, ignoring Frank's assurances that she was not, unaware that Frank was only sure of this fact after having an affair with Karen himself. Assuming that Karen and Jez must be on the verge of becoming a couple, Sheila invited Jez around for dinner to help set them up and at the end of the night happily left them upstairs to have sex. Forced into a corner, Karen admitted the truth to Jez and assured her that she was straight but still wanted to be friends.
Jez later became a surrogate for an unknown couple, proclaiming her happiness at the large payments and free dental care they were providing. She later left The Jockey in the hands of Carol Fisher to go on maternity leave and during a talent show Carol informed the customers that Jez had given birth to a son named Jason and had 18 stitches though since she had only "incubated him for a nice couple" they should stop leaving cards with no stamps behind the bar to pass along.
Jez never did return from maternity leave and cut all ties from the Chatsworth estate, Carol left Chatsworth in the gap between Series 4 and 5, and The Jockey was promptly taken over by Karen and Jamie, confirming that Jez had left the pub for good.
In series 5, although Jez has left the pub and in not seen, there are still notices posted around The Jockey regarding drinks and meals prices signed 'Jez'