This article investigates the asynchronous controller design of uncertain semi‐Markov jump systems (SMJSs) with a self‐triggered scheme to reduce network resource occupation and attenuate disturbance. More precisely, a self‐triggered strategy is designed for the asynchronous controller synthesis process, which could improve network communication efficiency and deal with the mode jump asynchronous phenomenon problem of systems and controllers. To achieve the desired interference rejection performance of SMJSs, sufficient criteria are constructed in terms of model transformation and mode‐dependent Lyapunov functional method. Then, the matrix technique is used to synthesize asynchronous controller design. Eventually, our proposed approach is validated via a practical illustration on a single‐link robot arm.