The mechanical properties of LB-PBF-build 33CrMoV12 steel grade were investigated for different material states (Asbuilt, tempered, double tempered and quenched-tempered) and discussed in relation to the inherited microstructures. As-built LB-PBF samples have higher tensile properties and lower impact toughness compared to the wrought material. A cellular microstructure was observed, consisting of martensite cells surrounded by nano-sized austenite. The presence of 25% of austenite is explained by a strong carbon segregation evidenced by high resolution SIMS (Secondary Ion Mass Spectroscopy). Further tempering causes an important drop in impact toughness. XRD showed that austenite was destabilized, forming brittle phases. Double tempering doesn't restore the impact toughness to the value of conventional material. Finally, austenite quenching and tempering allows to restore static and impact toughness similar to the value of conventional material, indicating a sufficient homogenization of the carbon microsegregations induced by fast solidification during LB-PBF process .