Crack-free bioactive nanocoatings embedded with uniformly distributed silica-rich bioactive spherical aggregates were successfully prepared in situ by controlling the micellization of a SiO₂–CaO–P₂O₅ sol using the tri-block copolymer P123 followed by dip-coating onto a bio-inert glass substrate and calcined. These hierarchically designed nanocoatings embedded with such bioactive glassy nanospheres (BGNS) enabled to induce the deposition of a densely populated, uniform, and well-developed needlelike crystalline carbonated hydroxyapatite coating reminiscence of the mineral phase of natural bone within a short immersion time in simulated body fluid. The BGNS nanocoatings also supported the growth and attachment of human gingival fibroblasts. The results suggest that these newly designed composite nanocoatings are noncytotoxic, capable of supporting rapid and homogeneous calcium phosphate deposition as well as subsequent crystallization, and likely to be promising candidates for inert glass reinforced bone implants.