Biomimetic mineralization can lead to advanced crystalline composites with approachable chemicals under ambient conditions. An exceptional example is biomimetic nacre with its superior fracture toughness. Learned from numerous biominerals, we anticipate that mineralized thin coatings with hierarchical architectures would exhibit emergent (multiple) structural functions, nicely bridging the boundaries between engineering and functional materials. Nevertheless, the syntheses of such thin coatings with uniform micro-/nano-textures on the macroscopic domain (over several centimeters) remains challenging in the realm of materials chemistry. Our group developed the seeded mineralization for fabrication of continuous prismatic-type thin CaCO3 coatings. Their distinct exterior micro-/nano-textures could be obtained via morphosyntheses in the presence of different soluble polymeric additives and the polymeric substrates used underneath. These hierarchical thin coatings can exhibit multiple structural functions including the under-water superoleophobicity, ultra-low adhesion force of oil in water, and remarkable stiffness/strength. Moreover, this approach could proceed on fibrous substrates to obtain crack-free thin coatings, so that a modified nylon mesh could be employed for oil-water separation driven by gravity. This biomimetic bottom-up approach based on seeded mineralization not only opens the door for deposition of hierarchical mineralized thin coatings on planar and fibrous substrates, but could be readily extendable for the synthesis of advanced thin coatings with a broad spectrum of engineering and functional constituents.