Smart textiles have generated significant importance because of the advent of portable devices and easy computing, however, they did not replace the conventional electronics on the whole however, this development is now advanced to the fabrication of wearable technologies. The aim of this research paper was to develop a flexible microscale conductive fiber for real-time strain monitoring applications. This conductive fiber was developed by depositing conductive silver (Ag) nanoparticles on the surface of Nylon-6 polymer yarn by electroless plating process to achieve smallest uniform coating film over each filament of the Nylon yarn without jeopardizing the integrity of each material. The sensitivity of this Nylon/Ag conductive fiber was calculated experimentally and gauge factor was found to be in the range of 21–25 which showed that it had high sensitivity to the applied strain. Then, Nylon/Ag conductive fiber was tested up to fracture under tensile loading and a good agreement between mechanical and electrical response was observed with reproducibility of the results. The results demonstrated the way to design a cost-effective microscale smart textile for strain monitoring. This Nylon/Ag conductive fiber can then be used in a wide range of high strain applications such as in-situ structural health monitoring or for medical monitoring because of their high sensitivity, flexibility, and stability.