The Prosecuting Attorney is the chief law enforcement officer of Livingston County and is charged with the duty to see that the laws are faithfully executed and enforced to maintain the rule of law. An elected official with a four-year term of office, the Prosecuting Attorney is independent of the Michigan Attorney General. The Prosecuting Attorney's office performs a wide array of legal duties.

Mission: To preserve and protect the rights, safety, and quality of life for the residents of Livingston County through diligent efforts to investigate and prosecute criminal offenses in Livingston County.

 William J. Vailliencourt, Jr.

 Office Responsibilities

  • Chief law enforcement official in the County
  • Reviews, authorizes and prosecutes violations of felony and misdemeanor criminal laws of the State of Michigan committed inside the County
  • Authorizes and prosecutes felony & misdemeanor juvenile delinquency offenses
  • Represents the People of the State of Michigan in criminal matters before the District & Circuit Courts; juvenile delinquency, parental neglect and miscellaneous probate matters in the Circuit Court/Family Division and the Probate Court, and appeals in the Court of Appeals and Michigan Supreme Court
  • Prepares child abuse and neglect petitions, and prosecute actions to terminate parental rights
  • Attends contested mental health commitment hearings
  • Files and prosecutes actions to establish paternity and family support order


Prosecuting Attorney
J.D., cum laude, Washington & Lee University School of Law (1986)
B.A., University of Michigan (1983)

Bill has served as Livingston County Prosecutor since January, 2013. Prior to his election, Bill had been an Assistant Prosecutor in Livingston County since 1995. Bill previously worked as an Assistant Prosecutor in Oakland County and worked in private civil practice. For thirteen years, Bill also volunteered as a reserve police officer. Bill is an experienced trial attorney and appellate practitioner who has argued numerous cases in the Michigan Supreme Court and Court of Appeals.

Bill currently serves as the President of the Prosecuting Attorneys Association of Michigan (PAAM) and has served as chair of its Best Practices Committee, Legislative Committee, and as vice-chair of its Amicus and Court Rules Committee. A recipient of the PAAM's Boyle Appellate Advocacy Award, he is a frequent instructor for prosecutors, police officers, judges, and defense attorneys on trial advocacy, search and seizure, sentencing, and other criminal law and procedure issues. Bill is a contributing author for the Institute for Continuing Legal Education and has previously served as an active member of the Supreme Court's Committee on Model Criminal Jury Instructions.

Bill is a past President of the Livingston County Bar Association and currently serves as a member of the Board of Directors of LACASA, Livingston County's domestic violence and sexual assault crisis center.