The present disclosure provides exemplary arm immobilization devices for a person and associated methods of use. Thus, in one aspect, the disclosure provides a device including or comprising an outer shell including an internal cavity and a configurable structure disposed within the internal cavity of the outer shell. The outer shell can be configured and dimensioned to accommodate an arm of a person thereon. Expansion or contraction of the configurable structure can drive expansion or contraction of the outer shell. In another aspect, the disclosure provides methods for immobilizing an arm of a person that include providing an arm immobilization device and supporting the arm of the person with the outer shell and the configurable structure.