An alkyl halide containing monomer, 2-chloroethyl methacrylate (CEMA) was synthesized via the chorination of 2-hydroethyl methacryalte and polymerized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The kinetics of the controlled/living radical polyemrization (CRP) was systematically investigated. The chain end livingness of poly(2-chloroethyl methacrylate) (PCEMA) was confirmed by the chain extension with methyl methacrylate (MMA) under RAFT polymerization conditions. PCEMA with dangling alkyl chloride groups was directly azidated through a nucleophilic substitution with sodium azide, affording a polymer with an azido group at each repeating unit. The resulting polymer was readily available for post-polymerization modifications by various click reactions. These strategies may open new perspectives toward more effective and milder conditions for azide involving reactions.