A Google Volley developer is responsible for managing HTTP requests in Android applications. They utilize the Volley library, a product of Google, to facilitate networking operations, improve load times, and streamline data retrieval and uploading processes. They work on creating custom requests, handling image requests, implementing request queuing, and managing synchronization issues. Volley developers also handle error scenarios and cache responses, ensuring seamless user experience. They play a crucial role in enhancing the performance and efficiency of Android applications by making the network operations smoother and faster.