Activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP) was introduced by Matyjaszewski and coworkers in 2005. The development of AGET ATRP has profound industrial implications because it lowers the amount of necessary catalyst, while still allowing excellent control over molecular weight and molecular weight distribution. Herein, we highlight recent works on the mechanistic understanding of AGET ATRP towards the advance of catalysis and the design and synthesis of functional polymers, with a particular emphasis on: (a) mechanistic understanding of AGET ATRP; (b) reduction of catalyst concentration; (c) aqueous-phase systems by AGET ATRP; (d) iron-mediated AGET ATRP; and (e) functionnal polymers designed by AGET ATRP. AGET ATRP is a robust tool due to its simplicity, broad applicability, and its ability to prepare previously inaccessible well-defined polymeric materials.