A non-volatile memory device includes a non-volatile memory cell array, an input/output pad unit, and a peripheral circuit. The non-volatile memory device executes an operation requested by a controller. The input/output pad component provides a path through which a command and data related to the operation requested by the controller are input to the non-volatile memory device, and through which a result of execution of the requested operation is output to the controller. The peripheral circuit is configured to be loaded with a plurality of commands provided by the controller, to temporarily store program data provided by the controller to be written in the non-volatile memory cell array and data read from the non-volatile memory cell array, to adjust an execution order of the commands asynchronously with the controller based on an internal operation status of the non-volatile memory device, and to execute the commands in the adjusted execution order.