Our Team


CPA, Principal, Director, Tax Department Head

Small & Midsize Businesses
DEPARTMENTS: TaxWealth Management

Katie Hamilton, CPA, Principal, Director, Tax Department Head

Katie joined Maner Costerisan as a principal in 2018 and was elected to the firm’s Board of Directors in 2024. She also leads the firm’s Tax department, where she’s responsible for directing and managing Maner’s tax staff, the firm’s tax growth strategy and client service. Additionally, Katie consults on income, estate and gift tax planning for clients and is an active member of the firm’s High Net Worth and Small and Midsize Business industry teams. Katie joined Maner after spending most of her career in a top-20 national tax and consulting firm. During her time there, she gathered valuable experience helping clients sell businesses, transition wealth, avoid unnecessary taxes and plan and prepare for retirement with a tax-focused approach.

Driven to make an impact both in the community and with her clients, Katie is a strong advocate for taking a holistic approach to a client’s financial planning. She played an influential role in championing the launch of Maner Wealth, the firm’s wealth management service, in 2020. She continues to look for ways the firm can assist clients with their greatest needs, starting with their personal financial management.

Optimistic, relatable and a hard worker, Katie is not one to settle – she strives for her best and aims to help others improve, including the tax team. Her ability to connect with staff and clients are intangibles that make her one of the firm’s go-to resources for both career advice and tax strategy.

Named to the list of “10 Over the Next Ten” by the Lansing Chamber in 2019, Katie’s motivated to live her life to its fullest. She tries to enjoy the journey and not just the destination. She’s most proud of her family, becoming a partner at Maner and seeing all her hard work manifest into the life she has today. Katie credits her family for her success and continues to strive to make them proud.

A self-described thrill-seeker and fan of Michigan’s great outdoors, Katie loves camping. She and her family can be found downhill skiing in the winter and spending time near the water in the summer.

Katie lives in Dewitt, Michigan, with her husband of 18 years, John, and two kids, Graham and Harper.

I’m motivated every day by knowing I can help my clients sleep better at night. The ability to put someone at ease over an item that has been worrying them for decades is so meaningful. Watching the weight lifted off their shoulders, I can’t explain how gratifying it is.

Solving a problem for a client and finding unique ways to achieve results they didn't know was even possible… that’s what makes me excited to come to work every day.

Years of Experience



American Institute of Certified Public Accountants (AICPA)

Michigan Association of Certified Public Accountants (MICPA)

Greater Lansing Estate Planning Council (GLEPC)


Certified Public Accountant (CPA)