In this article, a novel fully distributed dynamic event‐driven strategy is designed for linear multi‐agent systems (MASs) containing unknown parameters under general directed graphs. Each agent can achieve consensus asymptotically by communicating with its neighbors and does not need to use global information, so the proposed dynamic event‐driven algorithm can work in a fully distributed manner. Existing fully distributed event‐based consensus works rely on two or more event monitoring conditions. Too much event monitoring logic will put an extra computational burden on the MASs; instead, for the first time, this article proposes a fully distributed event‐driven strategy with a single event monitoring condition under directed graphs. In addition, the proposed strategy (adaptive control law and event monitoring condition) does not involve the dynamics parameters of MASs and provides better applicability. Finally, we rule out Zeno behavior by showing that any adjacent event interval for each agent is greater than zero. The simulations verify our results.