A kernel-programming developer works on the core of an operating system, the kernel. They are responsible for designing, implementing, and debugging low-level software that interacts directly with the hardware. This includes managing resources like memory, processor time, and peripherals, and handling system calls from higher-level software. They must understand hardware specifications, write efficient and secure code, and troubleshoot complex issues. They also need to ensure compatibility with different hardware and software configurations. Their work is critical for system performance, stability, and security.