First Appearance: Episode 387 (1984)
Last Appearance: Episode 584 (1985)
Known Family: Mother - Heather O'Brien; Father
- Mike O'Brien; Brother - Jeff O'Brien (d. 1985); Uncle
- Jim O'Brien
Flings with Terry Hansen, Wayne Hamilton, Alan
Brandon and Gary Evans
Katie moves to Albert Park, Melbourne, with her
parents, Mike and Heather, and younger brother, Jeff,
in 1984. Her first priority is to find herself a job -
and she persuades her father to take her on in his lawnmowing
business, so that she can use the money she earns to buy
herself a computer: her dream is to develop a career writing
computer games. She finds herself attracted to both Andy
Green and John Palmer, but nothing happens with either
When businessman Roger Carlyle turns up in Albert Park,
Katie is worried: Heather used to work for Roger in Perth
but has always warned Katie to have nothing to do with
him because of his interest in young girls. However, when
Roger offers to help her with some contacts who might
be interested in her computer games, Katie finds herself
unable to say 'no'. Unfortunately, when Katie signs a
contract for her games, she discovers later that she's
signed away exclusive rights to every game she ever comes
up with. She blames Roger for misleading her - but, to
her surprise, Roger agrees to help her again by threatening
to take away all the business he puts his contact's way.
Roger's son, Luke, warns Katie that Roger is only being
so nice to her because he's a letch and he wants her.
Katie challenges Roger about this - and is astonished
when he admits that Luke is right. He then assures Katie,
though, that he's decided not to do anything about his
feelings for her.
Katie finds herself attracted to Terry Hansen - but after
discovering that he raped Jill O'Donnel, she runs a mile.
She calms down, though, and when Terry goes on trial for
kidnapping his baby daughter, Fee, Katie stands by him.
Terry is sent to prison in Ararat. Katie visits him whenever
she's able, but she's left devastated when Terry sends
her a letter in which he tells her that he's grateful
for the way she's stuck by him, but that the last thing
she needs is to be tied down with a guy with his sort
Katie meets Wayne Morrell when he's in Melbourne on business.
He takes an interest in her computer games and offers
to help her with some contacts if she's ever in Sydney.
After the way things have been in Melbourne, it doesn't
take Katie long to decide to move to NSW, where she moves
into Fiona Thompson and Irene Fisher's boarding house.
Wayne helps Katie land a contract to develop new computer
games - and as the two celebrate together, a passionate
kiss ensues. Katie quickly falls in love with Wayne -
despite being warned by several people that he's bad news.
She's therefore devastated when, just a short time later,
Wayne tells her that he thinks it's best if they end things,
as there's no chance of their relationship lasting forever.
He later reveals, however, that Karen Fox blackmailed
him into ending his relationship with Katie, but has backed
down, meaning they can be together again.
Wayne comforts Katie after she learns of the death of
her brother, Jeff, in a fire at the O'Brien house in Melbourne.
He then turns to Katie for support after rejection by
his father, Gordon, and business problems caused by Karen
Fox. However, when he tries to take things further than
Katie - who's a virgin - wants, Katie pushes him away.
Wayne reacts badly, accusing her of thinking only of herself.
The relationship comes to an abrupt end and Katie moves
back to Melbourne.
Katie soon finds Karen's son, Alan Brandon, taking an
interest in her - but when he, too, tries to take things
too far, Katie rejects him as well. After another altercation
with Wayne, in which he ends up snarling that Katie is
a stupid, frigid bitch, a horrified Katie tries to prove
him wrong by dressing-up provocatively and coming-on to
Andy Green. Andy, however, sees through her act and accuses
her of being a mess. An upset Katie concludes that nobody
wants her. However, when Alan asks for a second chance,
Katie agrees - and when Alan tries to take things further
this time, she lets him. Things don't get very far, though,
because they're sprung by a furious Beryl Palmer, whose
bedroom they're using!
Alan is badly injured when he's caught up in the explosion
of a boobytrapped wheelchair during a party at David Palmer's
house in the country. When Katie goes to visit him in
hospital, she meets surgeon Dr. Ross Newman - who quickly
charms her and invites her out for a drink. It's Ross
to whom Katie loses her virginity, after he gets her drunk.
The relationship develops - but sadly, Katie discovers
that Ross is two-timing her with Barbara Hamilton. A distressed
Katie realises that she's once again fallen for the wrong
When she then discovers that Ross may have kidnapped
Beryl Palmer's baby son, Robert, Katie decides to try
and find out if Ross is really behind it by pretending
to Ross that she forgives him. The plan almost works until
Ross discovers Katie going through the pockets of his
jacket. He flees, leaving Katie annoyed that her plan
Katie moves back to Sydney, where she moves into Charlie
Bartlett's house. When Wayne asks her to use her computer
to hack into the Hamilton company's accounts, his reasoning
- that he thinks the accountant is ripping-off the company
- is plausible enough for Katie to agree, albeit reluctantly.
She writes a program that provides Wayne with access to
all the company finances - but she then becomes suspicious
about his actions and reports them to Stephen Morrell.
There's a shock in store for everyone when it turns out
that the Wayne who was trying to rip Gordon off wasn't
really Wayne: it was a lookalike named Gary Evans!
Mike and Heather announce that they've decided to start
life afresh in Queensland and Katie decides to go with
them, leaving all her problems in Melbourne and Sydney