Fiber type devices are promising for applications in wearable and portable electronics. However, scalable fabrication of fiber electrodes with multifunctional performance for use in distinct fields remains challenging. Herein, high performance smart fibers based on Mo1.33C i-MXene nanosheets and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate hybrid paste are fabricated with an easily scalable spinning approach. The hybrid fibers produced by this method can be applied in both high-performance supercapacitors and electrochemical transistors (ECTs). When assembled into a fiber type asymmetric supercapacitor with reduced graphene oxide (rGO) fiber, a capacitance of 105 F g(-1) and an energy density of 37 mW h g(-1) were reached for a potential window of 1.6 V. The hybrid fiber based ECT shows high transconductance and fast response time. This work demonstrates the potential of i-MXene-based fiber electrodes for multifunctional applications, to aid in the development of the next-generation, high-performance wearable electronic devices.