Walter Jack commands the land-based Walter Team, one of three specialized divisions in the Rugger Team exploration and defense force. As pilot of Rugger #11, his vehicle forms the waist section of the combined super robot Dairugger. His team's vehicles first combine to create the Rickrugger before joining the full Dairugger formation.

Jack exhibits a charismatic and witty personality, often displaying a notably calm and patient demeanor compared to other team leaders. He maintains a level-headed approach during missions, frequently playing devil's advocate to counter impulsive decisions from colleagues. His leadership fosters loyalty and camaraderie among his squadmates, solidifying his role as the Rugger Team's effective second-in-command. The narrative portrays him as embodying stereotypical American traits.

His primary responsibilities involve coordinating land-based operations in support of the Rugger Team's planetary exploration and defense objectives against the antagonistic Galveston Empire. Jack's narrative function centers on operational command, emphasizing his consistent role as a stabilizing influence within the team dynamic and a key participant in Dairugger's deployment. His interactions highlight his position within the ensemble cast, particularly during mechanical combination sequences and combat engagements against Galveston Empire forces.