We investigated the dielectric and piezoelectric properties of -oriented 0.24Pb(In1/2Nb1/2)O3-0.46Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 (PIMN-0.30PT) single crystals (SCs) manufactured by continuous-feeding Bridgman (CF BM) within morphotropic phase boundary (MPB) region after field cooling alternating current poling (FC ACP). By optimized the FC ACP conditions of 4 kVrms/cm from 100 to 70 oC, the PIMN-0.30PT SC process attained ultrahigh dielectric permittivity (εT 33/ε0) of 8330 and piezoelectric coefficient (d33) of 2750 pC/N, and bar mode electromechanical coupling factor k33 of 0.96 with higher phase change temperature (Tpc) of 103 oC, respectively. These values are the highest ever reported as PIMN-xPT system SCs with Tpc > 100 oC. The enhancement of these properties of the PIMN-0.30PT SC is attributed to the induced low symmetry multi-phase supported by phase analysis. This work indicates that FC ACP is a smart and promising method to enhance piezoelectric properties of relaxor-PT ferroelectric SCs including PIMNT, which provide a route to a wide range of piezoelectric device applications.