In a press release, he said that he resigned "in the best interest of the organization." The announcement followed a closed session of the board.
He told the Almanac that he has no definitive plans yet for what comes next, but he doesn't intend to apply for Menlo Park's currently open city manager position.
Asked whether the philosophical clash with the supervisors included conflict over the county's decision to build a new jail instead of choosing a less expensive alternative, Mr. Boesch said in an email: "I guess that some may point to the difference in opinion about the jail project. I have always provided the Board with my best advice and recommendations, with a clear understanding that they are, ultimately, the policy and decision makers."
Board President Carole Groom said it wasn't a specific issue, just overall general direction and vision that led to the parting of ways.
Mr. Boesch's final day in office will be Nov. 15. He's agreed to work from home after that to help the transition to an interim manager until Dec. 31, drawing upon unused leave for payment. As county manager, he earned $270,233 annually plus a $13,338 transportation allowance on top of other benefits. His severance package includes three-and-a-half months' salary plus health insurance through April 2012, as long as he doesn't find another job before Dec. 31.
The $1.16 million home loan Mr. Boesch received from Menlo Park in 2002 was transferred to San Mateo County; according to a county spokesman, the loan is to be repaid in full upon the sale of the house or by Dec. 31, 2012, whichever comes first.
"It has been an honor and a privilege to lead this organization during especially challenging times," Mr. Boesch said in the statement. "I will forever treasure this experience and the many fond memories and friendships."
He was city manager in Menlo Park between July 2000 and February 2007, when he was named assistant county manager. He took the county manager post in late 2008, upon the retirement of John Maltbie, who was county manager for 19 years.
"I have a real passion for working on problems that on the surface seem intractable," Mr. Boesch said in the statement. "What I have learned in my career in public service is that almost any problem is solvable if you bring together the people involved and demonstrate a genuine commitment to working in partnership toward a solution."
Mr. Boesch has a master's degree in public administration from the John F. Kennedy School of Government at Harvard University and previously served as community development director in Nashua, New Hampshire, and in Sunnyvale.
Ms. Groom, noting Mr. Boesch's many contributions, said the board will look nationwide for a new manager.