In one aspect, a system for monitoring seedbed floor conditions within a field may include a frame and a wheel coupled to the frame. The wheel may be configured to support the frame relative to a soil surface of the field as the frame is moved across the field. The system may also include a support arm pivotably coupled to the frame and a disc coupled to the support arm, with the disc configured to penetrate the soil surface of the field and roll relative to a seedbed floor within the field. Furthermore, the system may include a sensor configured to detect pivotable motion of the support arm relative to the frame. As such, the pivotable motion of the support arm may be indicative of variations in a profile of the seedbed floor as the ground engaging assembly is moved across the field.