This study focuses on the fatigue crack growth (FCG) in laminated metallic composites (LMCs) consisting of Al-based materials with dissimilar yield strength. By conducting FCG experiments assisted by in situ far-field microscopy, the formation and the role of the observed toughening mechanisms in LMCs were analyzed both in qualitative and quantitative terms. Consequently, on the one hand, it was found that the crack deflection mechanism observed when the crack approaches the interfaces from the softer to the stronger layers greatly reduces the FCG rate near the interfaces (local effect). On the other hand, the crack bifurcation mechanism in the softer layers, starting at the interfaces at the crack transition from the softer to the stronger layers, leads to the formation of a complex crack network and thus reduces the FCG rate locally and in all of the subsequent layers (long-range effect). Additionally, FE analysis and FCG experiments on bimetal specimen were performed to gain a better understanding of the contributing factors on which the formation of these toughening mechanisms in LMCs is based.