The advancement of multifunctional soft devices in robotics, biomedical engineering, and wearable technologies increasingly demands material systems that integrate structural compliance with embedded sensing capabilities. This study investigates the potential of Foam Additive Manufacturing (FAM) using thermoplastic polyurethane (TPU) filled with carbon-based conductive additives, aiming to produce lightweight, deformable, and piezoresistive structures through in situ microcellular foaming during Fused Deposition Modelling. A systematic process optimization was performed by varying solubilization and extrusion parameters—including blowing agent absorption and desorption times, extrusion temperature and speed, and nozzle diameter—to control foam morphology at both the micro- and macro-scale. Morphological analysis via scanning electron microscopy (SEM) enabled the qualitative evaluation of bubble distribution and process-dependent structural transformations.