John

There are multiple characters with the first name of "John" or "Jon" in the series:
 * Sgt. John Davis, the character from Call of Duty 2
 * Cpt. John Price, the character from Call of Duty 4: Modern Warfare and Call of Duty: Modern Warfare 2
 * Cpl. John Smith, the character from Call of Duty 2: Big Red One
 * Lt. Jon Elliot, the character from Call of Duty 2: Big Red One