Who Is Naruto's Father?
The identity of Naruto's father has been the subject of speculation for Naruto fans for a long time. There have been heated debates - even full-blown internet flaming wars - about the mystery that is Naruto's father.
The Fourth Hokage Theory
Most people believed that Naruto's father was the Yondaime or the Fourth Hokage. The resemblance between the Yondaime and Naruto is striking - they both have blue eyes and yellow hair and they even have the same smile. And since Naruto is an orphan and the fourth died fighting with the Kyuubi - it all made sense.
Some people even went so far as to believe that the Yondaime, though it was clearly stated that he died fighting the Kyuubi, somehow survived and lived on to become the Akatsuki leader. They believed that everything - from the sealing of the Kyuubi inside Naruto until the hunting of the Jinchuuruki by the Akatsuki - was all part of an elaborate plot concocted by the genius mind of the Fourth Hokage. They believed that what was shown about the Yondaime was just a hoax, he was actually evil despite the fact that all the people of Konoha loved him and that he was willing to die for them.
However, there were many people who disagreed with these believers of 'Yondaime is Naruto's father theory' because they couldn't understand why a father would seal something like the Kyuubi inside his own son. Some believed that it would just be 'too obvious' and that Kishimoto can't possibly write something so obvious - there has to be a twist. Some believed that the Yondaime was Naruto's uncle, or brother, or some other distant relative - just not his father.
There were even people who believed that the Akatsuki leader (who they believed was not Yondaime) was actually Naruto's father. And, for some reason, he was hunting his own son. This theory was reinforced by the fact that the Akatsuki Leader's shadow looked somewhat like he had the same hair as Naruto. And when the Akatsuki's leaders face was revealed to have a striking resemblance to Naruto too, this theory gathered more supporters. And they believed that a Star Wars scene with the Akatsuki Leader saying "Naruto, I am your father" was not such a far off possibility.
There were other theories - some so farfetched and random that you'd have to wonder what the fans smoked in order to come up with it. But all those theories were dispelled once Chapter 367 of the manga came.
Chapter 367 is a perfect example of how the simplest answers are almost always the right ones. It how did kakashi get mangekyou sharingan out that the blatant was actually true and the Fourth Hokage really is Naruto's father. Jiraiya and Tsunade confirmed it all and even revealed the Yondaime's name to be Namikaze Minato.
But if the fourth is Naruto's father, then why is his name Uzumaki Naruto and not Namikaze Naruto? Where does the Uzumaki come from? It turns out that, for some reason, Naruto got his mother's surname instead of his father's. And it's not really heartless for Minato to seal Kyuubi inside Naruto since it was, after all, his dying wish that Naruto be treated as a hero for having to contend with having a monster inside him. He died believing that the villagers would love Naruto, he had no idea that they would do the opposite. This chapter has yet to be made into a Naruto episode, but it should be revealed in Naruto Shippuden pretty soon.