The Newark (N.J.) Star-Ledger said the rock star donated the instrument for the cause and played four songs at Wednesday night's "Stand Up for Heroes" fundraiser at the Beacon Theatre.
The buyer of the guitar presented it to a serviceman at the show as an expression of gratitude, the newspaper said, without identifying either person by name.
The foundation was created to aid those affected by war. It is named for the ABC News journalist who was critically wounded by a roadside bomb while covering the war in Iraq in 2001. He has since recovered from his injuries and resumed his reporting career.