A compiler plays a vital role in programming by translating high-level source code written in programming languages, such as C++ or Java, into machine code that a computer can execute. This translation is essential since computers operate on binary code. The compiler performs various tasks, including syntax analysis, optimization, and error checking, enabling developers to catch issues before execution. Additionally, compilers can produce intermediate code for further transformations or optimizations. In essence, compilers are crucial for creating efficient and functional software applications.