A C# MVC developer designs and builds web applications using Microsoft's .NET framework and the Model-View-Controller (MVC) architecture. They create models (data structures), views (UI components), and controllers (business logic handlers) in C#, ensuring smooth data flow between these elements. They also perform debugging, testing, and troubleshooting to maintain optimal application performance. In addition, they collaborate with front-end developers for UI integration and work with databases using Entity Framework. They ensure code quality and standards, maintain documentation, and may also be involved in requirement analysis, design discussions and deploying applications.