John joined the County Attorney’s Office in 2001 and he became a Chief Deputy County Attorney in 2011. In March 2022, John was appointed by the Board of Supervisors as County Attorney.  In addition to representing the Board of Supervisors, John also represents the County Executive Officer and advises the Superior Court.

In the community, John served for over eight years as a Planning Commissioner for the City of Pacifica, twice serving as the Commission Chair.  He is also active in his church, the First Presbyterian Church of Burlingame, where he has served as a deacon and presently serves as a member of the church’s personnel committee and governing session.  John was also an officer on both active duty and in the Army Reserves, where he served in a variety of assignments, including as a military police platoon leader, a military intelligence team leader, and judge advocate officer. 

John’s past experience in the County Attorney’s Office includes substantial litigation of civil cases in state and federal court, and representation of the following County departments and outside agencies:

  • County Executive’s Office
  • Chief of the County Health System
  • San Mateo County Medical Center and Clinics
  • Real Property Services
  • Planning & Building
  • Boards and Commissions
  • Sequoia Union High School District
  • San Mateo Union High School District
  • South San Francisco School District
  • Woodside School District
  • Special Education litigation
  • Affordable Housing initiatives



  • Undergraduate: UC Berkeley, B.A. Latin American Studies (with High Honors)
  • Phi Beta Kappa
  • Order of the Golden Bear
  • Law School: UC Berkeley School of Law
  • Order of the Coif
  • Other education:
  • United States Army Judge Advocate General School Advanced Course
  • United States Army Command and General Staff College

Prior Experience

Before coming to the County Attorney’s Office, John was employed as an associate with Sullivan & Cromwell in Washington, D.C. and he served for one year as a judicial law clerk for the Honorable Maxine M. Chesney, of the United States District Court for the Northern District of California.  He was also an associate with Heller, Ehrman, White & McAuliffe and an Assistant District Counsel with the Immigration and Naturalization Service, both in San Francisco. 


John D. Nibbelin headshot
John D. Nibbelin
County Attorney
(650) 363-4757