This paper investigates the issue of active fault-tolerant control for multi-agent systems using an event-triggered mechanism, aiming to achieve state-consistency control under a leader–follower framework. The proposed control protocol consists of two main components: leader input estimation and fault tolerant controller design under an event-triggered mechanism. Firstly, a leader–follower error system is constructed, where the leader's input is considered as a supplementary vector for the system state, resulting in an augmented error system. Then, a distributed state observer is designed for this augmented error system to transform the leader's input estimation problem into an augmented state estimation issue. Furthermore, an event-triggered mechanism is designed to optimize network communication resources by updating the control law only when specific triggered conditions are met. Next, taking into account the errors introduced by the distributed observer and event-triggered mechanism, the problem of determining the state error feedback gain matrix is transformed into a linear matrix inequality problem using H∞ robustness design and Lyapunov stability analysis methods. Finally, the effectiveness of this theoretical framework is validated through a practical example involving several VTOLs.