“Personal relationships with clients is what sets us
apart. We like to work one on one with our clients to
analyze their unique operating environments and
customize the best strategic plans.”

Why choose us

Since 1994, we have been serving clients ranging in size from Fortune 500 companies to local businesses and non-profits. We believe that ongoing client communication and partner availability is essential to providing high-quality, high-value professional services. From inception to dissolution, we walk side by side with our clients, expertly navigating the rapidly evolving environment they face today.

Mitzi E. Sullivan CPA, PLLC | Firm ManagerAbout the Owner

Certified Public AccountantAs the owner and manager of the Mitzi E. Sullivan CPA, PLLC, Mitzi oversees all departments and focuses on strategic and financial business planning for every client. Mitzi started her professional career at Ernst & Young as an auditor, primarily in oil and gas. She has over 30 years of experience as a CPA serving clients in numerous industries including real estate, professional services, construction, manufacturing, and retail. As an entrepreneur, Mitzi has a passion for business and takes pride in helping clients strategize for success.

  • Bachelor’s in Accounting at UTA
  • QuickBooks ProAdvisor

Mitzi E. Sullivan CPA, PLLC is proud to call Decatur, Texas home. We also offer virtual services to clients nationwide.

Our Team

Nick Grantham | Tax Manager

BBA, University of North Texas, 2015
BBA in Accountancy, University of North Texas, 2022
MS in Accountancy, University of North Texas, In Progress
Quickbooks ProAdvisor


Nick graduated from the University of North Texas in Marketing and has worked in taxes for 2 years. He is currently pursuing his master’s degree after finishing his bachelors in Accounting. Once Nick has completed both degrees he will become CPA certified.


Stacey Hanna | Business Service Associate

Attended the University of North Texas – General Business
Quickbooks ProAdvisor


Stacey attended the University of North Texas while studying general business. She has over 10 years of experience in bookkeeping, human resources and customer service. She currently assists clients with a variety of business services and is a QuickBooks Online ProAdvisor.

Gabriela Vargas | Staff Accountant

BS in Accountancy, University of North Texas, 2020
MS in Accountancy, University of North Texas, 2022


Gabriela joined M.E. Sullivan, CPA, PLLC as an intern. Upon graduating, she was promoted to full-time staff accountant. She currently assists a variety of areas, including Managed Accounting Services and personal and non-profit tax. Prior to joining the team, Gabriela held an internship with Clifton Larson Allen LLP in assurance.

Jessica Sullivan | Business and Accounting Service Manager

BS in Accountancy, Lubbock Christian University, 2019

Quickbooks ProAdvisor


Before joining Mitzi E. Sullivan CPA, PLLC, Jessica started her professional career as an auditor for Ernst & Young. Jessica graduated with honors in Accounting with a minor in Spanish. She specializes in bookkeeping, auditing and non-profits.

Mary Findley | Office Manager 

Senior at UNT Dallas in Human Services
Quickbooks ProAdvisor


Mary is a senior at UNT Dallas working on her bachelor’s degree in Human Services Management and Leadership. Mary joined Mitzi Sullivan’s team in 2022 and specializes in client communication and transactions.