A CruiseControl developer focuses on the implementation and maintenance of the CruiseControl continuous integration tool. They create scripts to automate software builds and tests, detect any integration problems early, and fix them promptly. They configure the system to monitor the repository for changes and trigger a new build when changes are detected. They also work on improving system performance, adding new features, and troubleshooting issues. Moreover, they collaborate with other developers to ensure code changes are integrated smoothly and efficiently. They play a key role in maintaining the quality of the software development process.