Boards must actively govern AI deployment to balance capturing value and managing risks, as AI oversight is now a fiduciary responsibility. Two common failures are under-engagement, where boards lack understanding and miss scaling AI benefits, and over-acceleration, where rapid deployment without controls causes costly harm. Effective governance involves five key responsibilities tailored to AI: defining corporate purpose and ethics related to AI use; ensuring strategy captures value amid changing competitive dynamics; overseeing assets and capabilities needed for execution; managing AI-specific risks with appropriate controls and audits; and adapting leadership evaluation to ensure executives can guide AI initiatives responsibly. The STAR framework offers a practical approach for quarterly AI oversight.