For many applications of dielectric elastomer (DE) actuators, it is desirable to endow the DE with a high dielectric constant (ε), high breakdown field, and good flexibility. In this study, a high-ε nanocomposite acrylic elastomer (ACM)-g-copper phthalocyanine (CuPc) was fabricated, in which the CuPc oligomer was grafted onto the backbone of ACM. This grafted composite exhibited several benefits over the physically blended one. Transmission electron microscopy micrographs indicated that the size of the grafted CuPc was in the range 15–30 nm, which was more than 25 times smaller than that of the simply blended one. At room temperature, ε of ACM-g-CuPc (with 15 wt % CuPc) reached 303 at 100 Hz. The remarkable enhancement in the dielectric response could be attributed to the greatly strengthened exchange coupling effect and the Maxwell–Wagner–Sillars polarization mechanism. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 39975.