Author Summary Candida albicans is a fungus that resides on the skin and in the gastrointestinal tract of humans and other mammals. However, this commensal organism is also capable of proliferating and causing disease in people who have received antibiotics, who are immunocompromised, or who have suffered injury to epithelial layers. We previously identified a novel transcription factor called Sef1 that promotes C. albicans virulence by activating the expression of iron uptake genes in iron-poor environments, such as the host bloodstream. However, in iron-replete environments such as the gastrointestinal niche, the SEF1 gene is repressed by a second transcription factor called Sfu1. Here, we report our discovery of a series of post-transcriptional regulatory events that determine the intracellular localization, stability, and activity of Sef1 protein. Mutants that disrupt these post-transcriptional events alter C. albicans virulence in a mammalian model of disseminated infection. The existence of multiple levels of regulation speaks to the importance of Sef1 in C. albicans virulence and suggests that close titration of Sef1 activity is important for adaptation to distinct microenvironments within the mammalian host.