A surgical stapling device having a rotating knob locking mechanism, and a method of using the surgical stapling device is disclosed. The surgical stapling device includes a housing, an actuation member, an elongated body portion rotatably supported on the housing, and a locking mechanism for preventing the rotation of the elongate body portion, the locking mechanism being automatically engaged upon actuation of the actuation member. The stapling device further includes a knob for rotating the elongated body portion. The locking mechanism includes a pivotably mounted member configured to engage the knob. The stapling device may further include an articulating tool assembly and an articulation lever for articulating the tool assembly. The articulation lever may be disposed on the knob for rotating the elongated body portion.