The last decades have been witness of an ever-growing interests for the synthesis and application of metal–organic frameworks (MOFs). However, most of the current synthetic procedures produce MOFs in powder state. In this work, hybrid foams were fabricated via in situ synthesis of leaf-like zeolitic imidazolate frameworks (ZIF-L) into nanocellulose at room temperature using water as solvent, followed by a gelatin matrix incorporation and freeze-drying. The foams are ultralight weight and are highly porous with densities ranging from 19.18 to 37.4 kg·m−3. The shapeability, hierarchical porosity, and low density of the formed foams offer promising potentials for applications such as CO2 sorption. The dispersion of ZIF-L into the cellulose network increases the material accessibility and may open new venues for further MOFs processing.