An environmentally stable mode-locked fiber laser based on nonlinear polarization rotation is experimentally demonstrated. The laser is based on a novel laser configuration that has negligible low-power steady-state reflectivity from one side and, consequently, no CW gain. The laser is self starting and the configuration is implementable as an all-fiber laser with standard polarization-maintaining fiber-pigtailed components. A pulse duration of $5.6\mathrm{ps}$ is obtained at a repetition rate of $5.96\mathrm{MHz}$ and at an average power of $8\mathrm{mW}$ . As an application of the proposed laser configuration, $213\mathrm{mW}$ of supercontinuum $(600–1750\mathrm{nm})$ was demonstrated from a fiber laser system with no sections of free-space optics.