A contact safety and trigger mechanism for use with a pneumatic fastener in order to permit efficient pneumatic fastener actuation mode selection. A rotating rod is included in a contact safety assembly which is constructed to slide toward/away from a driver housing, defining a piston for securing a fastener disposed within the piston's path of travel. The rotating rod includes a first shoulder or ledge and a second shoulder which is off-set from the first shoulder. The rod may be rotated in order to orientate the selected shoulder, to function as a stop for a pivoting trigger assembly, which is constructed to contact a pneumatic valve, to initiate a fastening event in-which a fastener is driven into a workpiece. The configuration of the rotating rod permits for selection between a contact actuation mode wherein movement of the contact safety initiates securing of a fastener and a sequential actuation mode in which the trigger assembly is manipulated by a user to trigger securing of a fastener after the contact safety has be depressed towards the driver housing.