Fibers that harvest mechanical energy via the triboelectric effect are excellent candidates aspower sources for wearable electronics and functional textiles. Thus far however, their fab-rication remains complex, and exhibited performances are below the state-of-the-art of 2Dplanar configurations, making them impractical. Here, we demonstrate the scalable fabrica-tion of micro-structured stretchable triboelectricfibers with efficiencies on par with planarsystems. We use the thermal drawing process to fabricate advanced elastomerfibers thatcombine a micro-textured surface with the integration of several liquid metal electrodes. Suchfibers exhibit high electrical outputs regardless of repeated large deformations, and cansustain strains up to 560%. They can also be woven into deformable machine-washabletextiles with high electrical outputs up to 490 V, 175 nC. In addition to energy harvesting, wedemonstrate self-powered breathing monitoring and gesture sensing capabilities, making thistriboelectricfiber platform an exciting avenue for multi-functional wearable systems andsmart textiles.