John works as the main news anchor mouse in the “PawPet News” skits. For a mouse he has an atypical deep voice. He keeps mixing up facts about the news he reads, which means that the news director has to correct him at least once per episode.
John's name resulted from the inability of Atkelar to come up with catchy names, especially under time pressure. Since the character is a mouse, the last name “Mouser” was a desperate attempt not to use “Mouse” on it's own. For the first names the only thing that came to mind was “John Doe” which was abbreviated to “John D.” to make it not that obvious.
The character is based on the Folkmanis puppet “mouse with west”.