We report an efficient glass-ceramic fiber laser and show that its slope efficiency 30 is not compromised by the presence of Nd-doped fluoride crystals embedded within the core of the single-mode optical fiber. In contrast, the spectroscopy (fluorescence and gain spectrum) of the Nd 3+ ions is dramatically changed by the ceramming process, an indication of strong partitioning of the rare-earth ions into the CdF 2 PbF 2 YF 3 crystal environment. The enormous potential for a new range of optical devices based on transparent glass-ceramic materials is highlighted.