Growing environmental concerns associated with synthetic materials have intensified the demand for sustainable alternatives derived from renewable sources. In addition, the increasing global population has led to a surge in the demand for food products including juice, resulting in the generation of substantial quantities of byproducts, which are organic waste with the potential for valorization. This study investigated the bioconversion of carrot pomace (CP), waste generated in the juice industry, into fungal biomass to produce mycelium-based foams. Filamentous fungus (Aspergillus oryzae) was cultivated on carrot pomace through a submerged process in a bubble column bioreactor. The analysis of the scanning electron microscopy (SEM) confirmed the presence of the fungal mycelium and CP residues in the material recovered from the bioreactor. This material was mixed with water, and the suspension was subjected to different grinding cycles in an ultrafine grinder, and mycelium-based foams were then formed via freeze-molding and freeze-drying. The resulting foams exhibited an average density of 21.1 kg/m3, with compressive resistance values of 5.8 kPa at 10% deformation and 20.5 kPa at 30% deformation. These mechanical properties are comparable to those of commercial lightweight foams, as indicated by the Ashby material plot. These findings demonstrate the potential of mycelium-based foams as an alternative to synthetic materials, contributing to waste valorization and development of environmentally friendly materials.