The primary role of a product owner in Agile methodologies is to define and prioritize the product backlog, ensuring that the development team delivers maximum value to stakeholders. This involves gathering and analyzing user feedback, setting clear objectives, and making informed decisions regarding feature implementation. The product owner acts as the liaison between stakeholders and the development team, ensuring alignment with the project's vision. By actively managing the backlog and providing continuous feedback, the product owner facilitates effective communication, rapid iterations, and ultimately, the successful delivery of a product that meets user needs and expectations.