In this paper, the electric-field-induced strain behavior and energy storage performance of MnO-doped 0.65Bi0.5Na0.5TiO3-0.35SrTiO3 (NBT-ST-xMn) lead-free ceramics has been investigated. After the introduction of MnO into NBT-ST ceramics, pinched and double P-E hysteresis loops with high Pmax and negligible Pr can be observed due to the introduction of defect dipoles. As a result, a relatively high strain of 0.22% with ultra-low hysteresis of 14% was achieved under a moderate electric field of 60 kV/cm at x=1.0 mol.%. Excellent energy storage performance of 1.14 and 1.17 J cm-3 with a high η of 83 and 80% are achieved at x=0.5 and 1.0 mol.%, respectively. Meanwhile, high electrostriction coeffcient of 0.022 m4C2 with pure electrostrictive characteristics was obtained at x=0.5 mol.%. The results illustrate that the proper selection of base composition and effective chemical modifier can made the NBT-ST an outstanding candidate for actuators and energy storage devices.