Refinement of the FePt grain size for heat-assisted magnetic recording (HAMR) media was explored by utilizing high melting point metals Pt and W as seed layers. Unlike the W, the Pt seed layer promotes a good epitaxial growth and leads to a higher degree of L10-ordering in FePt films. It also substantially refines the FePt grains from big islands into smaller particles. For the FePt-C nanogranular film, the Pt seed layer improves the wettability and favors a single-columnar growth. Thus, the Pt seed layer provides a new valid approach to optimize the microstructure and magnetic properties for next-generation FePt-based HAMR media.