The surface modifications are necessary to alter the inherent surface physical/chemical properties of materials in terms of adhesion, wettability, friction, biocompatibility etc. for using in textile, electronic and biomedical industries. Surface modifications are usually made by grafting of polymer brushes to the solid substrates. The grafting process allows controlling and manipulation of surface properties without changing the chemical structure of polymers. Besides their chemical structures, grafting density of polymer brushes and average distance between the polymer chains attached to the surface are also important parameters, affecting the intended use of the grafted materials. Synthesis of functional polymer brushes is generally carried out by one of surface-initiated controlled/living free radical polymerization techniques, namely Atom Transfer Radical Polymerization (ATRP), Nitroxide-Mediated Polymerization (NMP), Photoiniferter-Mediated Polymerization (PIMP) and Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT). This review reports the strategies of these techniques for generating polymer brushes and summarizes the applications of polymer brushes in multiple fields.