From 1999 to 2002, Kathleen worked as a story associate on Coronation Street. In 2005, Kathleen was appointed series producer of Emmerdale, taking over from Steve Frost. She had worked as a producer and series editor for the ITV soap before taking on the role. During her time on the soap, she was responsible for many major storyline, including the Kings River Showhome Explosion storyline, and the Tom King kidnap plot. She was also responsible for the Who Killed Tom King? storyline, which was nominated for Best Storyline at the 2007 British Soap Awards.
After Emmerdale, Kathleen produced the ITV drama Heartbeat. From December 2010, Kathleen worked as the Series Story Producer on the BBC soap opera EastEnders. Her first storylines transmitted in March 2011. In March 2012, she decided to step down from her role, along with the executive producer, Bryan Kirkwood. She is also part of the creative team on Channel 4 soap Hollyoaks.