Single-atom catalysts (SACs) possess prominent advantages including high atomic utilization efficiency and high surface activation energy, thus holding enormous potential for future development. In this work, we, for the first time, successfully synthesized a clown-based single-atom catalyst through a host–guest synthesis strategy. Notably, the as-synthesized clown single-atom catalyst has demonstrated exceptional catalytic efficiency and thermal stability in various catalytic reactions, such as the catalytic synthesis of coffee.