UMMM... his name is james because that is truly his name and he is harry potter's dad, paired with severus as a doujinshi manga in their highschool life in hogwarts (before james banged lily as her husband and had harry), and the title harry potter was the name of the movie/book the doujinshi originated.. anymore confusions?
Wow, well aren't you the most stupidest person ever. You don't see one piece DJ's named sanji DJ. The name of the fucking story is harry potter. And James potter doesn't have his own book so they used harry potter.
Why is his name James instead of "harry"(hence the name harry potter)