The synthesis of new nanohybrid catalysts with a tunable structure and the exploration of their synergistic behaviors have captured substantial attention. In this work, amorphous molybdenum disulfide/single‐walled carbon nanotubes (MoS₂/SWNTs) composites are synthesized by a facile hydrothermal process with the assistance of l‐cysteine. We varied the mass ratio of sodium molybdate (the in situ Mo source) to SWNTs, this method provides a well‐defined pathway to enable the morphological control over the evolution of MoS₂ from nanospheres to nanofilaments, nanorods, and nanosheets. Among the as‐obtained samples, the MoS₂/SWNTs (1:1) hybrids, which displayed a 3 D architecture that consisted of nanorods, exhibited the highest activity in the hydrogen evolution reaction (HER). Compared with pure MoS₂, the MoS₂ nanosheets that decorate the SWNTs have more highly exposed active edges, and the SWNTs in the center of the MoS₂/SWNTs nanorods can enhance the conductivity. We regulated the ratio between MoS₂ and SWNTs to obtain a balance between the number of active sites and the conductivity of MoS₂/SWNTs. Here, MoS₂/SWNTs nanorods exhibited a low overpotential of 195 mV at 20 mA cm⁻² and a low Tafel slope of 41 mV dec⁻¹ for MoS₂‐based HER catalysts.