A one-pot procedure for the synthesis of hyperbranched polyethylenes tethered with ATRP initiating sites by, chain walking ethylene copolymerization with an acrylate-type ATRP inimer, 2-(2-bromoisobutyryloxy) ethyl acrylate (BIEA) is reported. Because of its ability to incorporate acrylate-type comonomers and tolerance toward the alpha-bromoester group, the chain walking Pd-diimine catalyst, [(ArN=C(Me)-(Me)C= NAr)Pd(CH3)(N CMe)]SbF6 (Ar=2,6-(iPr)(2)C6H3), allowed the successful synthesis of a series of hyperbranched copolymers tethered with 2-bromoisobutyryl groups at different densities. These copolymers may serve as polyfunctional macroinitiators for the ATRP of functional monomers to further synthesize core-shell structured functionalized copolymers with a hyperbranched polyethylene core grafted with side chains of the functional monomers.