The optimization of metal–matrix composite material is linked firstly with the intrinsic properties of the matrix and the reinforcement used and secondly with the reinforcement–matrix interfacial zone and the distribution/orientation of the reinforcement inside the metal–matrix. Flake powder metallurgy was used to fabricate graphite flake reinforced aluminum matrix (Al/GF) composites fabricated by vacuum hot pressing. Two types of aluminum powders morphology were used: spherical (AlS) and flake (AlF) powders. A higher thermal conductivity in the in-plane direction of the graphite flakes was obtained for Al/GF composite materials fabricated with aluminum flake powder. In addition to a better orientation of the GF in the flake aluminum matrix, a 3D puckered surface and plane surface are formed at the Al/GF interface in, respectively, AlS/GF and AlF/GF composite materials. Due to the morphology incompatibility between the graphite flakes and the spherical powder, the damaged inner structure of GF contributes to a limited enhancement of thermal conductivity in AlS/GF composite materials.