Carbon nanomaterials have been frequently used to physically inhibit the lithium polysulfide's shuttle in lithium–sulfur batteries, especially those crumpled structure of graphene. Here, a type of reduced graphene oxide fiber enwrapped nano-sulfur (rGOF@nano-S) hybrids were synthesized by a simple sulfur-containing-ion assisted microwave (MW) synthesis method and then utilized as a sulfur host for lithium–sulfur batteries. The synergistic reactions of MW treatments and sulfur-containing-ion force on the precursor GO nanosheets (NSs) have induced a well-crumpled fibrous structure, and simultaneously uniformly wrapped the nano-S particles in them, which would make the resultant cathodes achieve improved electrochemical performances. The rGOF@nano-S hybrid cathodes showed a high reversible capacity (886 mA h g−1 at 0.1 C rate), a high rate capability (remaining 61% at 2 C rate), and an excellent cycling stability (with a minimal decay rate of 0.04% per cycle over 800 cycles at 1 C), which are highly improved compared to those of the hybrids without MW treatments. In addition, the optimal MW treatment time on rGOF@nano-S hybrid cathodes were also explored to be 2.4 min under 700-W power. This work suggests that MW treatments would be a useful strategy for the preparation of high-performance cathodes for Li–S batteries.