committee member
A member of a formal committee, council, or board. Common in organizational, governmental, and business settings.
He was elected as a member of the executive committee.
Committee members, please share your opinions.
He became a member of the student council committee this year.
The class elected her as the library committee member.
My father has served as a neighborhood association committee member for five years.
委員 is a committee member chosen for a specific task or group, while 役員 is a more formal, often higher-ranking officer of an organization.
negotiating committee member; negotiator on a committee
rehabilitation worker