MahoneySabol Promotes Casey O’Brien to Partner
July 17, 2025
MahoneySabol, a regional certified public accounting firm based in Glastonbury, announced the promotion of Casey O’Brien, CPA to Partner. O’Brien brings nearly two decades of public accounting experience to his new leadership role.
O’Brien began his career with MahoneySabol in July 2008 after earning a Bachelor of Science degree in Accounting from the University of Connecticut. Over the past 17 years, he has steadily advanced within the firm, most recently serving as a Senior Audit Manager. In that role, he managed all aspects of the audit process for many of the firm’s most complex engagements, led client relationships, mentored and supervised staff, and helped drive quality and efficient service delivery within the attest department.
“Casey’s promotion to Partner reflects both his deep, technical expertise and his long-standing commitment to our clients and the success of our team,” said Michael Sabol, CPA, a Founding Partner at MahoneySabol. “He possesses a unique ability to manage the full spectrum of client needs, while also training and developing our staff. We are excited to see him take on this next challenge.”
In his new role as Partner, O’Brien will lead assurance engagements across a wide range of industries, with a particular focus on manufacturing, real estate, retail gasoline distribution, and transaction advisory services. He has extensive experience performing assurance and transaction advisory services for both publicly traded and closely held companies and provides consulting on complex accounting issues such as business combinations, consolidations, and equity-based awards.
A licensed Certified Public Accountant in the State of Connecticut, Casey is a member of the American Institute of Certified Public Accountants.
“As Casey steps into the Partner role, we look forward to his continued contributions in shaping the future of our attest practice,” added Sabol. “His leadership will be key as we expand our client relationships, pursue strategic growth opportunities, and continue to build a team known for excellence.”
About MahoneySabol
MahoneySabol, certified public accountants, provides comprehensive accounting, auditing, tax and business consulting services to a wide range of clients and industries. The firm’s 65-plus accounting professionals and administrative support staff serve clients throughout the region. MahoneySabol is committed to remaining true to its roots as a New England-based firm and fulfilling its original mission to be the premier regional accounting firm in its market area. The combination of local firm feel, national firm experience, and access to global resources through their independent membership in the BDO Alliance USA, allows MahoneySabol to serve clients unlike other firms in the New England marketplace. Founded in 1990, the firm has offices in Glastonbury and Essex.
MahoneySabol has been the title sponsor of the annual 5K at the Travelers Championship since 2016, with proceeds contributed to the Neuromuscular Care Center at Hospital for Special Care to benefit patients with amyotrophic lateral sclerosis (ALS or Lou Gehrig’s Disease).
For more information, visit us online at mahoneysabol.com.