Fibrous composite materials provide distinct advantages in large surface area and enhanced molecular transport through the media, lending themselves to diverse applications. Despite substantial development in synthetic methods, it is still lacking in insights into structure–property relationships that can correlate features of the functional materials to absorptive, transport, and catalytic performance of the composites. Herein, for the first time, a systematic structure–property–function analysis is provided for Zr‐based metal–organic frameworks (MOFs) coated onto polypropylene nonwoven textiles. MOF fraction on the fabric and defect density in MOF microstructures are controlled by an in situ seeded growth, where fiber surfaces are pretreated with metal‐oxide by atomic layer deposition. The best performing MOF‐fiber composite shows a rapid catalytic hydrolysis rate for a chemical warfare agent simulant, p‐nitrophenyl phosphate with t1/2 < 5 min, and a significant permeation restriction of a real agent GD‐vapor through the composite. Of added advantage is the observed moisture vapor transport rate of 15 000 g m−2 day−1 for the composite, which is notably superior to that of other commercially available chemical‐protective fabrics. The chemical‐protective composites realized in this work overcome the breathability/detoxification trade‐off and show promise for the materials to be deployed in a realistic field. [ABSTRACT FROM AUTHOR]