Christopher Sullivan, 22, was shot late Friday while trying to break up a fight between his brother and another man at a San Bernardino, Calif., residence.
Sgt. Gary Robertson says 19-year-old Ruben Ray Jurado turned himself in to authorities in Chino Hills on Monday.
Police say Jurado shot Sullivan at Friday night's party after getting into an argument with Sullivan's brother over football teams.
Sullivan's relatives say the Purple Heart recipient was hit twice by gunfire, which shattered his spine and left him paralyzed.
Sullivan was wounded in a suicide attack last year while serving with the 101st Infantry Division. He had been recovering in Kentucky.