Littlejohn's guiding-center mechanics, with the polarization drift included, is rederived from a Lagrangian. The respective collisionless kinetic guiding-center theory is then established. While single-guiding-center energy is exactly conserved here in time-independent fields, the self-consistent kinetic guiding-center theory presented here conserves the total energy of the guiding-center plasma and its self-consistent electromagnetic fields only to leading order in ϵ ≡ r_g/L. The present formalism seems to be relevant to the theory of drift waves and anomalous transport.