Bioactive polysaccharides are attractive targets for skin repair and immune modulation, yet lichen-derived polysaccharides remain underexplored. Water-soluble polysaccharides (WSPs) were isolated from Peltigera praetextata (PP) and P. aphthosa (PA) using the hot-water extraction method and were evaluated for their bioactivities in human health. Composition analysis (HPLC-SEC, FT-IR, and 1D/2D NMR) confirmed that the PP fractions were mannan-rich with a galactomannan-like profile, whereas the PA fractions were enriched in galactose with minor fucose content. PP polysaccharides exhibited significant pro-migratory activity in HaCaT keratinocytes compared with untreated controls. The NaCl-assisted hot-extracted fraction (2B) of PP showed dominant activity across assays, accelerating the scratch gap closure and elevating macrophage uptake with minimal cytotoxicity through an autophagy-dependent pathway. Autophagy behaviour was selectively modulated in RAW264.7 cells but largely unchanged in PC3 cells. Under basal conditions (non-LPS), nitric oxide levels were close to those of untreated controls for most samples. Cytotoxicity was modest overall, with selective cytotoxicity observed in PC3 cells compared with HaCaT keratinocytes. In contrast, galactose-predominant fractions were associated with lower basal nitric oxide output. These findings reveal a structure-activity relationship in which mannose-enriched fractions were associated with pro-migratory keratinocyte responses and enhanced macrophage function, while galactose-rich fractions attenuate inflammatory reactions. This work presents lichen-associated polysaccharides as potential candidates for applications in skin repair and immune modulation.