Lanmodulin (LanM), a lanthanide (LnIII) ion-chelating protein first discovered in Methylobacterium extorquens, has been applied to LnIII sensing and separations due to its high affinity for and potential for selectivity between the chemically similar ions of the lanthanide series. Three of LanM’s four EF hands coordinate a LnIII ion with high affinity, and binding of these ions induces a global conformational change from a largely disordered state to a more compact, ordered fold. While this transition has been broadly characterized, it is likely to be more complex than has previously been appreciated because metal binding induces not only the global conformational change but also local helix formation. Here, we describe kinetic, thermodynamic, and structural studies of the LnIII ion dependence of LanM’s conformational response. This detailed model of LnIII-induced protein folding contributes to the growing understanding of the biochemistry of LnIII ions and can be used to guide further applications of LanM.