As our understanding of the aging process progresses, so does the need for experimental animal models that allow a mechanistic understanding of the genetic and environmental factors involved. One such well-studied animal model is the freshwater polyp Hydra. Hydra are remarkable because they are non-senescent. Much of this non-senescence can be ascribed to a tissue consisting of stem cells with continuous self-renewal capacity. Another important fact is that Hydra’s ectodermal epithelial surface is densely colonized by a stable multispecies bacterial community. Here, we review key advances over the last decade that are deepening our understanding of the genetic and environmental factors contributing to Hydra’s non-senescent lifestyle. We conclude that continuously high activity of transcription factor FoxO contributes to continuous stem cell proliferation and supports robust colonization of epithelia with a stable microbiome. Understanding the complex process of aging requires a holistic view which includes the microbiome.