Metal nanofibers with excellent electrical conductivity and superior mechanical flexibility have great potentials for fabrication of lightweight, flexible and high-performance electromagnetic interference (EMI) shielding architectures. The weak interactions and large contact resistance among the wires, however, hinder their assembly into robust and high-performance EMI shielding monoliths. In this work, we used low fractions of polymers to assist the construction of lightweight, flexible, and highly conductive silver nanowire (AgNW) cellular monoliths with significantly enhanced mechanical strength and EMI shielding effectiveness (SE). The normalized surface specific SE of our AgNW-based cellular monoliths can reach up to 20522 dB·cm2/g, outracing that of most shielding materials ever reported. Moreover, this robust conductive framework enabled the successful fabrication of hydrophobic, ultraflexible and highly stretchable aerogel/polymer composites with outstanding EMI SE even at an extremely low AgNW content. Thus, this work demonstrated a facile and efficient strategy for assembling metal nanofiber-based functional high-performance EMI shielding architectures.