Cortactin is an important molecular scaffold for actin assembly and organization. Novel mechanistic functions of cortactin have emerged with more interacting partners identified, revealing its multifaceted roles in regulating actin cytoskeletal networks that are necessary for endocytosis, cell migration and invasion, adhesion, synaptic organization and cell morphogenesis. These processes are mediated by its multi-domains binding to F-actin and Arp2/3 complex and various SH3 targets. Furthermore, its role in actin remodeling is subjected to regulation by tyrosine and serine/threonine kinases. Elucidating the mechanisms underlying cortactin phosphorylation and its functional consequences would provide new insights to various aspects of cell dynamics control.