Alkali-intercalated graphite compounds represent a compelling modification of carbon with significant application potential and various fundamentally important phases. The intercalation of graphite with alkali atoms (Li and K) using liquid ammonia solution as a mediating agent is reported. Alkali atoms dissolve well in liquid ammonia, which simplifies and speeds up the intercalation process, and it also avoids the high temperature formation of alkali carbides. Optical microscopy, Raman, and electron spin-resonance spectroscopy attest that the prepared samples are highly and homogeneously intercalated to a level approaching stage-I intercalation compounds. The method and the synthesis route may serve as a starting point for the various forms of alkali-atom-intercalated carbon compounds (including carbon nanotubes and graphene), which can be exploited in energy storage and further chemical modifications.