Andreas Borgeas launched his campaign at a fundraiser Tuesday evening.
Several of his supporters, including Mayor Ashley Swearengin, were there as he made the announcement.
Borgeas currently serves district two, which covers Northwest Fresno.
He'll try to win the seat being vacated by longtime county supervisor Susan Anderson.
"Fresno County needs a bold, new direction, and I believe I have the energy, drive, experience and independence necessary to bring desperately needed change to Fresno county and make our community more prosperous and safer," Borgeas said.
Borgeas will face commercial real estate broker Larry Fortune, who announced his candidacy for the position in May.