The position of County Administrator was created by the Home Rule Charter adopted on November 8, 2005. The County Administrator serves as the chief administrative officer and supervises the administrative offices of the executive branch (that are not overseen by elected executives).

The County Administrator is a key position in helping to provide for an accountable and responsive County government by ensuring effective, efficient and economical administration in accordance with the County Charter, the Washington State Constitution and other applicable federal, State and local laws, as well as County Policy

The County Administrator exercises the executive powers of the County that are not expressly vested in other specific elected officers by this Charter. Specific duties are outlined in Section 3.43 of the Home Rule Charter. The County Administrator is responsible for such duties as presenting the annual budget, overseeing use of technology, reporting to the County Council on activities of the government, reporting on budget expenditures and compliance, and carrying out the policies of the County Council.

Pete Rose began serving San Juan County on July 24, 2006. In a 27 year career in local government administration, Pete spent the most recent 14 years as City Manager of Woodinville, City Administrator of Medical Lake and City Administrator of Quincy — all cities located in Washington. He has held a number of regional board positions. The most important to his work in San Juan County were as a 7½ year board member of A Regional Coalition for Housing (an affordable housing group) and a 7 year trustee for the Washington Cities Insurance Authority (a municipal risk pool).