An experimental investigation on the cyclic stability of solutionized Ni_44.8Cu₅Ti_45.2Hf₅ and Zr-substituted Ni_44.8Cu₅Ti_40.2Hf₅Zr₅ (atomic percent, at%) medium-entropy shape memory alloys (MESMAs) was carried out. The shift of the peak temperature for the forward B2 (Formula presented.) B19′ transformation in Ni_44.8Cu₅Ti_45.2Hf₅ alloy after 50 differential scanning calorimetry (DSC) cycles was measured to be 23 °C, substituting 5 at% Zr for Ti increased it to 41 °C. No residual strain accumulation was observed in Ni_44.8Cu₅Ti_45.2Hf₅ alloy after 10 thermal cycles under a tensile stress of 200 MPa, and meanwhile the shape memory strain increased from 5% to 6.5%. A pseudoelastic strain (ε^PE) of ≈2.7% was obtained in Zr-substituted Ni_44.8Cu₅Ti_40.2Hf₅Zr₅ alloy at 55 °C (A_f + 10 °C) for a maximum deformation (ε_max.) of 4.4%. In addition, the stability of pseudoelasticity in Ni_44.8Cu₅Ti_40.2Hf₅Zr₅ alloy during 100 loading–unloading cycles was examined in the solution annealed (1000 °C for 1 h) and aged (400 °C for 1 h) conditions. The results showed that aging treatment could effectively retard the degradation of pseudoelasticity in the alloy. These preliminary findings suggest that the idea of increasing chemical complexity in NiTi-based SMAs holds promising potential in developing novel SMAs with enhanced cyclic stability.