Maintaining reliable cooperative behaviors and ensuring the control efficacy of networked agent systems (NASs) subjected to unknown nonlinear influences, including the boundedness of control error, is vital for the robustness and security of the system, particularly in scenarios where precise cooperative motion is imperative. Nevertheless, it is a real struggle for the majority of current robust adaptive control approaches to provide an accurate quantitative assessment of the control error bounds. To confront this challenge, this paper investigates the prescribed performance group consensus control problem for nonlinear networked agent systems subject to uncertainties and actuator faults. A prescribed performance robust control strategy is proposed to achieve the group consensus of nonlinear NASs with uncertainties and actuator faults and guarantee the group consensus errors converge within the preset performance envelope, which operates without prior knowledge of the nonlinear characteristics or their bounds of NASs. According to the Lyapunov theory, the stability of the control strategy is proved. Additionally, numerical simulations are conducted to validate the efficacy of the proposed control scheme.