Abatement of chemical hazards using adsorptive metal‐organic frameworks (MOFs) attracts substantial attention, but material stability and crystal integration into functional systems remain key challenges. Herein, water‐stable, polymer fiber surface–oriented M–TCPP M = Cu, Zn, and Co; H2TCPP = 5,10,15,20‐tetrakis(4‐carboxyphenyl)porphyrin 2D MOF crystals are fabricated using a facile hydroxy double salt (HDS) solid‐source conversion strategy. For the first time, Cu–TCPP is formed from a solid source and confirmed to be highly adsorptive for NH3 and 2‐chloroethyl ethyl sulfide (CEES), a blistering agent simulant, in humid (80% relative humidity (RH)) conditions. Moreover, the solid HDS source is found as a unique new approach to control MOF thin‐film crystal orientation, thereby facilitating radially arranged MOF crystals on fibers. On a per unit mass of MOF basis in humid conditions, the MOF/fiber composite enhances NH3 adsorptive capacity by a factor of 3 compared to conventionally prepared MOF powders. The synthesis route extends to other MOF/fiber composite systems, therefore providing a new route for chemically protective materials. Chemical protective metal‐organic framework (MOF)/fiber composites highly adsorptive for NH3 and 2‐chloroethyl ethyl sulfide (CEES), a vesicant sulfur mustard simulant, are fabricated. The facile synthetic route employed here for the composite systems shows not only synthetic generality, but also extends to other MOF/fiber composite systems that cannot be readily facilitated by conventional synthetic approaches.