In order to synthesize miktoarm star-branched polymers consisting of poly(2-(perfluorooctyl)-ethyl methacrylate) (P(F8H2-MA)) segments insoluble in most organic solvents, a novel methodology based on a new concept by using a THF-soluble in-chain-benzyl bromide (BnBr)-functionalized AB diblock copolymer, polystyrene (PS)-block-P(F8H2-MA), as a key building blocks is proposed. The methodology involves the following three reaction steps: (1) preparation of in-chain-(3-tert-butyldimethylsilyloxymethylphenyl) (SiOMP)-functionalized PS-block-P(F8H2-MA) by means of living anionic polymerization, (2) a transformation reaction of the SiOMP group into BnBr function, and (3) a coupling reaction of the resulting in-chain-BnBr-functionalized PS-block-P(F8H2-MA) with another living anionic polymer(s). With this methodology, a variety of well-defined 3-arm ABC, 4-arm A(3)B, ABC(2), and ABCD miktoarm star-branched polymers consisting of P(F8H2-MA) (B) segments was successfully synthesized. Thus, the proposed methodology satisfactorily works and opens a new route for the synthesis of miktoarm star-branched polymers consisting of insoluble arm segment(s).