"It was time to create a change and go with a new level of responsibility, new people and new clients," said Ms Preston-Lett.
Although she has only ever worked as an accountant and for just the two firms, Ms Preston-Lett said she loved the variety clients brought to the job.
"Your clients are constantly changing and doing new things all the time," she said.
At KPMG, she quickly moved through the ranks, promoted to senior manager and then to director in 2005, where she took on responsibility for developing and servicing her own client base in KPMG's private enterprise division; an evolution of the small and medium sized enterprise division.
In January 2011, she was made partner, private enterprise. She also works with her peers nationally, and is the firm's Tauranga staff partner, a human relations role.
Glenn Keaney, KPMG office managing partner, said Ms Preston-Lett was a great role model. "She's in charge of making sure staff morale is high and she really listens to people," he said.
"Tracy has added a lot to the partnership in her approach. She tackles things up front and she isn't afraid to ask the tough questions. Clients have a lot of trust in her and she has the ability to form really close relationships, with a high level of service and insightful work. She thinks outside the square."
Mr Keaney said she was also noted for regularly updating clients with useful data and thoughtful leadership insights related to their business.
Ms Preston-Lett said she was an avid Twitter user, mining it for useful management and business articles for her clients.
She is also a member of early-stage funding group Enterprise Angels, which helps her keep an eye on what is happening in the start-up space.
"One of the main things I've learned over the years is that business owners are really good at what they do," she said. However, she noted that the role of external advisers had evolved as a result of the challenges of working through the global financial crisis.
"Post-GFC, the rubber has really hit the road in terms of how people collaborate now," she said.
"I've seen how bringing a number of external advisers together - the accountant, the lawyer, the business mentor and the bank - can make a good business great.
"It used to be much more competitive, but people came out of the GFC viewing business collaboration through different lenses."
Dave Macfarlane, co-founder of IT services company Cucumber, and a property developer and investor, who has worked with Ms Preston-Lett for many years, described her as pragmatic, down to earth and excellent to deal with.
"We engage people like Tracy to look after us and help grow us and she's done a great job," he said.
"I've got interests from IT to start-ups to property to manufacturing and she has a handle on all of them. Tracy has a great grasp of how business functions and operates, and adds a lot of value from a development and growth potential perspective."
Beach and boating is way to relax
Tracy Preston-Lett, her husband, Travis, regional manager for EDL Fasteners, and their son, Matheson, 9, enjoy beach and boating life.
They recently bought a small place in Waihi Beach where they spend weekends.
"It's a nice little treasure only 40 minutes up the road," she said. "My husband is a mad fisherman and we enjoy getting out on the water. For us, it's about enjoying what Tauranga and the Western Bay has to offer."
She is also a trustee for Tarnished Frocks & Divas Charitable Trust, the theatre on the catwalk show, which aims to empower women over 40 by providing a platform of self-discovery, inspiration and creative expression. "The show inspires people to challenge themselves, create new goals and be a positive influence on family, friends and the wider community."
Ms Preston-Lett is also treasurer for the Tauranga Sport Junior Rugby Club, where her son plays, and helps out with KPMG partners and staff at the Breakfast Club for Merivale School.
Tracy Preston-Lett
Role - Partner, private enterprise, KPMG Tauranga
Born - Whanganui, New Zealand
Age - 45
First job - Trainee accountant
