A Managed COM developer is responsible for creating, managing, and integrating COM (Component Object Model) components in .NET applications. They use interoperability services provided by the .NET framework to interact with COM objects. Their tasks include designing and implementing reliable COM objects, ensuring smooth communication between COM and .NET components, resolving interoperability issues, and maintaining code quality. They also collaborate with other developers to optimize system functionality and troubleshoot any issues that may arise. Furthermore, they may need to provide technical support and documentation for the COM components they develop.