Global regulators play an important role in secondary metabolite biosynthesis and morphological development in filamentous fungi. LaeA, a key global regulator in filamentous fungi was found in 2004, regulating the expression of a variety of fungal natural product gene clusters. Besides regulation of beneficial metabolism, fungal toxin biosynthesis and morphological developmental processes, laeA also contributed to activating the expression of cryptic gene clusters and resulted in generating novel secondary metabolites. Although the mechanism of LaeA on gene activation is still unclear, it has set the stage for understanding the fungal regulatory network and discovering new natural products. This review highlight its discovery, function and regulatory mechanism in filamentous fungi.