A biscuit joiner for engaging a workpiece to form a slot sized to receive a carpentry biscuit is provided. The biscuit joiner has a base with a fence surface for engaging the workpiece. The fence surface has an elongated opening formed therein. A motor is fixed to the base, and has a drive shaft. A link has a first end pivotally mounted to the base, and a second end rotatably mounted to a rotary cutter blade. A drive mechanism connects the drive shaft to the rotary cutter blade. An actuator is operable to pivot the link relative to the base. Pivoting the link causes the rotary cutter blade to shift relative to the fence surface between a retracted position in which the rotary cutter blade is within the base, and an extended position in which the rotary cutter blade extends through the elongated opening in the fence surface to cut the workpiece. Alternatively, a slidable carriage is received on the base. The motor and rotary cutter blade are mounted to the carriage. The carriage is slidable relative to the base toward and away from the fence surface. The actuator is operable to slide the carriage to cause the rotary cutter blade to shift between the extended and retracted positions.