Ordered graphene films have been fabricated on Fe-treated SiC and diamond surfaces using the catalytic conversion of sp3 to sp2 carbon. In comparison with the bare SiC (0 0 0 1) surface, the graphitization temperature is reduced from over 1000 °C to 600 °C and for diamond (1 1 1), this new approach enables epitaxial graphene to be grown on this surface for the first time. For both substrates, a key development is the in situ monitoring of the entire fabrication process using real-time electron spectroscopy that provides the necessary precision for the production of films of controlled thickness. The quality of the graphene/graphite layers has been verified using angle-resolved photoelectron spectroscopy, scanning tunneling microscopy and low energy electron diffraction. Graphene is only formed on treated regions of the surface and so this offers a method for fabricating and patterning graphene structures on SiC and diamond in the solid-state at industrially realistic temperatures.