In this paper, an improved and generic design of counterweights that can be applied to achieve complete rotational balance of disk cams is proposed. A pair of integrally formed counterweight bumps is added to a disk cam with an arc-slot hole in order to achieve static and dynamic balancing conditions simultaneously. The radially outside contour of each counterweight bump is exactly part of the cam profile. With the aid of analytical expressions and derived geometric properties for the cam profile, a systematic approach for obtaining the theoretical solutions of the integrally formed counterweights is established based on derivations of balancing conditions and a solution procedure. An optimization model is also established. Subsequently, to verify the feasibility and effectiveness of the proposed design, two hardware models were designed and built for measuring their induced vibrations and shaking forces. Experimental results revealed that the counterweighted disk cam could suppress the induced vibrations and reduce the induced shaking forces, and especially could effectively suppress the intensity of the resonance phenomena. Hence, the proposed design can improve the dynamic performance of disk cam mechanisms.