Core cross-linked star (CCS) polymers with radiating arms composed of high-order multiblock copolymers have been synthesized in a one-pot system via iterative copper-mediated radical polymerization. The employed "arm-first" technique ensures the multiblock sequence of the macroinitiator is carried through to the star structure with no arm defects. The versatility of this approach is demonstrated by the synthesis of three distinct star polymers with differing arm compositions, two with an alternating ABABAB block sequence and one with six different block units (i.e. ABCDEF). Owing to the star architecture, CCS polymers in which the arm composition consists of alternating hydrophilic-hydrophobic (ABABAB) segments undergo supramolecular self-assembly in selective solvents, whereas linear polymers with the same block sequence did not yield self-assembled structures, as evidenced by DLS analysis. The combination of microstructural and topological control in CCS polymers offers exciting possibilities for the development of tailor-made nanoparticles with spatially defined regions of functionality. (C) 2015 Wiley Periodicals, Inc.