Learn about the Team at Town of Barnstable, including our Treasurer/Collector and Director of Finance.
Photo of Sean O’Brien

Sean O’Brien


Sean O’Brien joined the Town of Barnstable in 2022 as the Town Treasurer/Collector. As the Treasurer/Collector Sean is responsible for:

 -Managing all Town borrowings
 -Processing Town and School payrolls
 -Investment of surplus funds
 -Servicing existing debt and issuing new debt
 -Billing and collection of the Town’s revenue sources

Prior to joining the Town of Barnstable, Sean was the Treasurer/Assistant Finance Director for the Town of Littleton, the Assistant Finance Director for the Town of Natick, and the Senior Budget and Operations Analyst for the Town of Concord.

Sean earned a Master’s degree in Public Administration from Suffolk University and is in the process of becoming a Certified Massachusetts Municipal Treasurer and a Certified Massachusetts Collector. He is involved with the Massachusetts Collector Treasurers Association as well as the Government Finance Officers Association.

Photo of Mark Milne

Mark Milne

Director of Finance
(508) 862-4660

Mark A Milne joined the Town of Barnstable in December 1997 as the Director of Finance after spending several years as the Comptroller for the Town of Amherst, MA and working in the public accounting profession where much of his work involved auditing government entities. 

In 2005, Mark spearheaded the efforts to consolidate the financial operations of the Town of Barnstable with the Barnstable Public Schools. This initiative won the Massachusetts Municipal Association’s Kenneth Pickard Innovation Award in 2006 and the consolidated operation remains in place today and Mark has presented on this effort on several occasions to professional organizations.

Under Mark’s direction the Town of Barnstable has received the GFOA’s distinguished budget presentation and financial reporting awards for the past 20 years. This effort has demonstrated the finance team’s and the Town Council’s commitment to provide comprehensive and transparent information when it comes to the town’s finances. Most recently, Mark directed a new transparency effort to include current and past years budget information on an Open Budget website that is updated on a regular basis so that those interested can track the town’s budget performance and view information on active and completed capital projects.

Mark received his undergraduate degree in Accounting from the University of Massachusetts, Amherst where he attended the Isenberg School of Management and earned a Masters in Public Administration from Suffolk University, Boston. He is actively involved in professional organizations promoting excellence in municipal finance and represents the State of Massachusetts on the Executive Board of the New England States Government Finance Officers Association. Mark is also licensed Certified Public Accountant in the Commonwealth of MA.

Currently, as Director of Finance for the Town of Barnstable, Mr. Milne oversees the Town’s financial functions consisting of the following departments: Accounting, Budgeting, Assessing, Procurement, Tax Collections and Treasury. In this capacity, he manages a total full-time staff of 31 people.  In his current role, one of the essential functions is the development and ongoing management of the town’s annual operating and capital budgets which total $285 million for Fiscal Year 2023.