Fugaku was also the one who taught Sasuke and Itachi how to perform the Fire Ball technique. However, Sasuke did not pick-up on the new technique as quickly as Itachi did, he knew Sasuke was not yet ready to learn the Jutsu. But Sasuke did not give up on the technique, he practiced all day long for days, he wanted to please his father. Sasuke had always noticed that whenever Itachi did something, his father would say "That's my boy" and was very proud of him. Sasuke wished that his father would tell him that too, and be proud of him, for something. Which it seems he never has. So he thought if he learned the Fire Ball technique, he would make his father proud. A while later, Sasuke had gotten a lot better at the technique, and decided it was time to show his father once again, to show him how much better he had gotten at it. After Sasuke showed Fugaku the technique, he silently walked away. So, of course, Sasuke kept practicing, he was very determined to make his father proud. He worked harder and longer than ever. And got even better at the technique after a while. He decided it was time to show his father again. After showing him his improvement for the second time, Sasuke created a huge fireball, not quite the size of his, but it was close. Fugaku looked surprised, Then he silently walked away, then stopped and said, "That's my boy." He then also said to follow his own path, not in the footsteps of his brother.
Later on, Fugaku had noticed that Itachi had been acting very strangely in recent time. He would often skip out on his missions and randomly disappear at times. When Itachi got into a fight with the shinobi that were investigating the death of Uchiha Shisui, Fugaku, not knowing that his son had actually committed the murder, broke it up and took responsibility for the problems Itachi had caused, and claimed that all of the missions he had been doing have made him tired and has affected his thinking, he just needed rest. Itachi agreed and apologized for his actions. Soon after that, Fugaku, and the whole Uchiha clan, other than Uchiha Sasuke, were killed by Itachi.