Fullerene with encapsulated lithium cation, Li+@C60, can be regarded as an alkaline cation owing to the spherical shape and positively charged Li+ cation. We present the crystal structure and phase transition of a rock-salt-type Li+@C60 crystal that consists of the freely rotating Li+@C60 cations and orientationally disordered PF6− anions at 400 K. The orientations of the C60 cages and PF6− anions are perfectly ordered below TC=370 K, whereas the Li+ cations are thermally hopping within the cages even at 155 K. A gradual localization of the Li+ cations at polar two positions in each C60 below 100 K and a negative thermal expansion of the static C60 are demonstrated.