Kirsten spent her time overseas working at international law firm Herbert Smith Freehills in London, where she made partner 10 years ago. Before she moved to London in 2004, Kirsten was an associate in Russell McVeagh's litigation team.

Kirsten has been involved in some of the largest cases in the Commercial Court of England and Wales in recent years. She played an instrumental role in achieving a historic settlement for Royal Bank of Scotland on its landmark shareholder rights issue litigation, following the near collapse and government bailout of the bank in October 2008, for which she was recognised on The Lawyer's Hot 100 list. Most recently, she has advised TSB following its well-publicised IT issues, conducted an investigation for Ted Baker into allegations of misconduct by its CEO, and been involved in several significant professional negligence cases, defending accountants and lawyers.