Kat arrives in Walford on 18 September 2000, along with her family: father Charlie (Derek Martin), sisters Lynne (Elaine Lordan), Little Mo (Kacey Ainsworth) and Zoe (Michelle Ryan), and grandmother Mo Harris (Laila Morse). Kat embarks on a brief fling with Steve Owen (Martin Kemp), much to the annoyance of his girlfriend Mel Healy (Tamzin Outhwaite). She finds work in The Queen Victoria public house as a barmaid, where she is an instant hit with the customers. Fiercely defensive of her sisters, Kat embarks on a feud with Little Mo's abusive husband Trevor Morgan (Alex Ferns) – though has a fling with Lynne's boyfriend Garry Hobbs (Ricky Groves). Much to Zoe's frustration, Kat is often over-protective of her. When Zoe announces her decision move to Spain with their uncle Harry (Michael Elphick), Kat refuses to allow her to go. She reveals that she is Zoe's mother, having been sexually abused by Harry aged thirteen. Zoe flees Walford, and Kat attempts suicide by cutting her wrists. She recovers, is romanced by local doctor Anthony Trueman (Nicholas R. Bailey), and later finds Zoe and brings her home. Their relationship improves, but after Kat breaks up with Anthony, he and Zoe begin an affair. Zoe disowns Kat for disapproving of their relationship, and later runs away when Anthony reveals that he is still in love with Kat.