Mandy arrives in Emmerdale to live with her uncle Zak, having been disowned by her father, Caleb. She finds work as a barmaid at The Woolpack, where her feisty personality makes her an instant hit with the locals. Mandy even set up a burger stall called Mandy's Munchbox, which did not last as it was blown up by brothers Jimmy and Colin Batty in March 1997. Mandy was initially very promiscuous but the arrival of vet Paddy Kirk in February 1997 proves to be a turning point in Mandy's life. She falls in love with Paddy and is willing to settle down and get married but their romance suffers problems. Mandy's cousin Butch overhears Paddy ridiculing their family and he tells Mandy so she orders Paddy out of her house and is heartbroken. Paddy leaves for Ireland where he has a job and returns to the village the following month. He and Mandy reconcile after he apologises to her family.
Paddy's mother Barbara disapproves of Mandy and convincing her that she will only make Paddy miserable if they marry, pays Mandy to marry Butch instead. Butch had always been in love with Mandy and readily accepted his cousin's proposal, marrying her in a secret registry office ceremony in November 1998. However, despite trying to make her marriage work, Mandy cannot ignore the fact that she truly loves Paddy and the former couple soon begin an affair behind Butch's back. Butch is livid when he discovers the truth and the Dingle family disowns Mandy for her infidelity, although her uncle Zak and his wife Lisa eventually come round after Paddy delivers their unexpected daughter Belle on Christmas Day 1998.
Following her divorce from Butch in 1999, Mandy marries Paddy and they live happily in domestic bliss. However, Mandy soon begins feeling inferior as Paddy is a university graduate and she is just a barmaid. With Paddy's encouragement, Mandy enrols in a college course in Hotten, but this proves to be the downfall in their marriage. Whilst at college, Mandy becomes attracted to her lecturer and they eventually embark on an affair. However, when she discovers that her lecturer is only using her for sex, a distraught and guilt-ridden Mandy comes clean to a devastated Paddy. With their marriage over, Mandy then departs the village to live with her best friend, Kelly Windsor, in London in December 2000. She returns briefly the following year in order to win Paddy back after realising the mistake she had made but after realising he is happy and settled with post office worker Emily Dingle, Butch's widow, Mandy admits defeat and leaves the village again.
After over a seventeen-year absence, Mandy returned to the village in January 2019 with her teenage son, Vinny, in tow. Her return was an inconclusive situation to the residents of the village and specifically her cousins Marlon and Sam, and ex-husband Paddy. However, at first, upon her return, Mandy was shady to reveal the truth of her return and claimed that it was for the simple reason that she wanted to attend the wedding of Marlon and Jessie Grant.
It became almost immediately apparent that Mandy was indeed back in the village when a fight between her and Chas Dingle broke out in the aftermath of the wedding ceremony. However, the pair finally made amends and Mandy was a condoling soul to Chas when she opened up about Grace, but that didn't stop Marlon demanding answers. Marlon thought that Vinny was Paddy's "secret son" and that Mandy had returned to tell him this, but Mandy revealed that Paddy is not Vinny's father. Afterwards, Mandy opened up that she found a source that could claim that the father Paddy thought was his, wasn't and it was, in fact, a boxer named Bear Wolf.
When Mandy left the village once more, with a macho man with a trendy car in tow, Vinny asked her why she didn't tell them the real reason she returned and Mandy replied that it wasn't the right time. During Mandy's absence, Bear Wolf was revealed to be Paddy's biological father, and he moved in with Paddy and Chas at The Woolpack after his unexpected arrival in the village.
"I'll do one, I'll do one!" - first line.
"You explain it to Uncle Zak. I'll give you 'till 5 o'clock. If you haven't owned up by then, I'd dig yourself a big hole, 'cause this farm is where World War III's gonna be startin'!" - to Lisa Dingle.