An Agile developer implements an iterative approach to software development, emphasizing flexibility, collaboration, and customer satisfaction. They work in small, collaborative teams to deliver functional components of software regularly, adapting to changes quickly. A Waterfall developer, on the other hand, follows a linear, sequential approach where each phase of the project must be completed before the next begins. They work with clearly defined requirements and a fixed plan, ensuring each stage (like design, testing, and implementation) is thoroughly completed before moving on, making it less flexible to changes but predictable. Both methodologies have unique strengths and are chosen based on project needs.