From 1989 to 2005, Jambois served as Kenosha County District Attorney. Jambois secured a conviction in the murder trial of Mark Jensen as a “special prosecutor” in Kenosha County Circuit Court. At the time of the events at issue in this case, Jensen was awaiting retrial in Kenosha County. Jambois joined the Dane County District Attorney's office in May 2015 as an assistant district attorney. Jambois alleges that he brought significant trial experience to the office, and he successfully prosecuted a number of cases during his tenure with that office.