Various systems and methods relate to an adaptive chair system having (i) a stowed mode in which members of the chair frame are compactly contained within a multi-function bag (MFB), and (ii) a deployed mode in which the multi-purpose chair is configured to transition between at least two seating modes. In an illustrative example, the chair may be provided with an adaptive frame which may be reconfigured to transition between the seating modes. For example, the chair may transition between any of a vertical/upright (chair) mode (e.g., FIG. 8B), a vertical/upright (chair) mode using trek pole handle segment(s) (e.g., FIG. 1C), a low-profile/recon (seat) mode (e.g., FIG. 2B), and a longitudinal/lounge mode (e.g., FIG. 2B). Various embodiments may advantageously provide an adaptive chair system in an ultralight form factor which may fulfill multiple functions including, by way of example and not limitation, seating, sun/rain canopy, footrest, or some combination thereof.