This study demonstrates the control of magnetic properties in monolayer and bilayer CrI₃ using electrostatic doping via a dual-gate field-effect device. In monolayer CrI₃, doping significantly modifies the saturation magnetization, coercive force, and Curie temperature, showing strengthened (weakened) magnetic order with hole (electron) doping. In bilayer CrI₃, doping drastically changes the interlayer magnetic order, causing a transition from an antiferromagnetic ground state to a ferromagnetic ground state above a critical electron density. The results reveal a strongly doping-dependent interlayer exchange coupling, enabling robust switching of magnetization in bilayer CrI₃ by small gate voltages. Electrical control of magnetism is attractive for magnetic switching applications due to its low-power consumption, high speed, and compatibility with semiconductor technology. The emergence of atomically thin magnetic insulators/semiconductors that can be integrated into van der Waals heterostructures has provided a unique system for electrical control of magnetism. The study shows that electrostatic doping is a more general approach for tuning the magnetic properties of both monolayer and bilayer CrI₃, providing a basis for future voltage-controlled spintronic and memory devices based on 2D magnetic materials. Pristine monolayer CrI₃ is a model Ising ferromagnet below ~50 K, with magnetic moments aligned in the out-of-plane direction. Pristine bilayer CrI₃ is an antiferromagnet with antiparallel magnetization from two ferromagnetic monolayers below ~58 K. The antiferromagnet-ferromagnet transition occurs at a low critical field of ~0.6-0.7 T, reflecting weak interlayer exchange interaction. The weak interlayer exchange interaction is susceptible to external perturbations, such as doping, providing a unique route for nonmagnetic control of the antiferromagnet-ferromagnet transition. The study fabricated dual-gate field-effect devices using the van der Waals assembly method. The magnetization of CrI₃ was characterized by magnetic circular dichroism (MCD) at 633 nm using a confocal microscope. The results showed that monolayer CrI₃ is a ferromagnet with a coercive force of ~0.13 T, and bilayer CrI₃ is an antiferromagnet that turns into a ferromagnet at a spin-flip transition field of ~0.6 T. The Curie temperature of monolayer CrI₃ was determined by measuring the temperature dependence of its magnetic sheet susceptibility. The study found that electrostatic doping significantly affects the magnetic properties of monolayer and bilayer CrI₃. In monolayer CrI₃, doping increases (decreases) the saturation magnetization and coercive force with hole (electronThis study demonstrates the control of magnetic properties in monolayer and bilayer CrI₃ using electrostatic doping via a dual-gate field-effect device. In monolayer CrI₃, doping significantly modifies the saturation magnetization, coercive force, and Curie temperature, showing strengthened (weakened) magnetic order with hole (electron) doping. In bilayer CrI₃, doping drastically changes the interlayer magnetic order, causing a transition from an antiferromagnetic ground state to a ferromagnetic ground state above a critical electron density. The results reveal a strongly doping-dependent interlayer exchange coupling, enabling robust switching of magnetization in bilayer CrI₃ by small gate voltages. Electrical control of magnetism is attractive for magnetic switching applications due to its low-power consumption, high speed, and compatibility with semiconductor technology. The emergence of atomically thin magnetic insulators/semiconductors that can be integrated into van der Waals heterostructures has provided a unique system for electrical control of magnetism. The study shows that electrostatic doping is a more general approach for tuning the magnetic properties of both monolayer and bilayer CrI₃, providing a basis for future voltage-controlled spintronic and memory devices based on 2D magnetic materials. Pristine monolayer CrI₃ is a model Ising ferromagnet below ~50 K, with magnetic moments aligned in the out-of-plane direction. Pristine bilayer CrI₃ is an antiferromagnet with antiparallel magnetization from two ferromagnetic monolayers below ~58 K. The antiferromagnet-ferromagnet transition occurs at a low critical field of ~0.6-0.7 T, reflecting weak interlayer exchange interaction. The weak interlayer exchange interaction is susceptible to external perturbations, such as doping, providing a unique route for nonmagnetic control of the antiferromagnet-ferromagnet transition. The study fabricated dual-gate field-effect devices using the van der Waals assembly method. The magnetization of CrI₃ was characterized by magnetic circular dichroism (MCD) at 633 nm using a confocal microscope. The results showed that monolayer CrI₃ is a ferromagnet with a coercive force of ~0.13 T, and bilayer CrI₃ is an antiferromagnet that turns into a ferromagnet at a spin-flip transition field of ~0.6 T. The Curie temperature of monolayer CrI₃ was determined by measuring the temperature dependence of its magnetic sheet susceptibility. The study found that electrostatic doping significantly affects the magnetic properties of monolayer and bilayer CrI₃. In monolayer CrI₃, doping increases (decreases) the saturation magnetization and coercive force with hole (electron