A Compiler Optimization Developer works on improving the efficiency of code execution by fine-tuning compilers. They identify and implement optimization techniques at various stages of code compilation, such as lexical analysis, syntax analysis, semantic analysis, and code generation. Their tasks involve enhancing code performance, reducing memory usage, and shortening execution time without altering the code functionality. They also ensure the accuracy and efficiency of the translation from high-level language to machine code. They may work on specific aspects like loop optimization, instruction scheduling, or dead-code elimination. Their role is crucial in ensuring smooth and efficient software performance.