The best method to deal difficult board directors is preventative – make sure that your agency’s objectives for board members are clear and that they can blend their own vision with that of the organization. This will limit the instances in which the advice of a member of the board can be counterproductive. If a problem does arise be proactive and don’t ignore poor behavior. Refusing to act will only make the situation worse.
Direct intervention is the first step – a meeting one-on-one with the person who is making trouble. Be calm and professional but also direct and express your concerns clearly. If this doesn’t work, consider an intervention in groups with a board member who the board respects and/or chair. You may want to check your agency’s Values statement and/or other governing document for words that could be used as a definition of acceptable behavior, which includes treating people with respect.
Another alternative is to ask someone to leave the board (ideally by a voluntary https://theboardmeeting.blog/how-do-you-keep-up-with-trends-in-your-industry decision, but if necessary by a vote of confidence). This will require some careful preparation and planning in advance of the meeting or discussion. Create a precise answer to the main issues you wish to discuss. Make sure your tone is respectful but firm. Do not be afraid to assert yourself.