An electric brake system and a method for controlling the same are disclosed. The electric brake system includes a hydraulic control device, a sensing unit, and a controller. The hydraulic control device generates hydraulic pressure using a piston operated by an electric signal generated in response to a displacement of a brake pedal. The sensing unit detects driver's braking intention. When an electronic stability control (ESC) of a vehicle operates, the controller calculates a change amount of stroke of the piston needed to output brake pressure corresponding to the driver's braking intention, and acquires the calculated stroke change amount so as to boost pressure of each wheel at a predetermined slope.