In a series filled with iconic character designs, few of Naruto's characters stand out like Itachi. While Itachi Uchiha is famous for his tragic backstory and his powerful abilities, it's his signature look that is seared into fans' minds. That's why it's so shocking that Itachi almost looked completely different.
Itachi is often seen clad in the signature all-black Akatsuki robes, adorned with various red clouds. While the Akatsuki robes are worn by every member of the villainous organization, Itachi's design still manages to stand out. His signature red eyes are immediately apparent, and the way he uses the robe like a sling for one arm instantly makes Itachi reminiscent of a samurai, as Naruto fan artists have picked up on. In contrast, his original design offers a completely new look at the character. Series author Masashi Kishimoto revealed what Itachi Uchiha’s original design may have looked like from its inception, and it's more or less a completely different character.
In the Fourth Naruto Guidebook, Kishimoto gave fans a look at what the first incarnation of Itachi Uchiha may have looked like. This character model sports a head-covering similar to Iwabe from Boruto, and a similar X-shaped chin scar to Danzo. The stance and attitude of this character model also seem to convey a completely different personality from the Itachi fans are familiar with. This earlier version of Itachi was also different in terms of his backstory. Originally, Kishimoto had planned on Itachi just being an evil person who gave Sasuke a reason to want to kill him. This soon changed, however, when Kishimoto decided to make Itachi a member of the ANBU Black Ops, a squad of covert assassins for the Hidden Leaf. Kishimoto decided that Itachi’s more tragic backstory suited his role in the story better, and his final design that fans are familiar with reflects that change.
The modern Itachi is much less cocky looking than his original design. Itachi always carried an ominous silence with him, never saying more than he needed to. The original design, however, looks more like the type of villain to be giving arrogant one-liners to the protagonist. It seems as if Kishimoto never really disassociated some of those design elements from the idea of a villainous character, as the Hidden Leaf’s one-time leader, Danzo famously sports the same scar seen in Itachi’s original design. Danzo being instrumental in the destruction of the Uchiha also seems like more than a coincidence when looking at how Kishimoto originally intended the series to play out. Itachi wasn't the only one with a design change, as even Team 7 sported an early 2000's look at one point.
Itachi’s original design is better suited for the more run-of-the-mill type villain. The condescending attitude and relaxed posture indicates a far more malicious and overbearing personality, similar to the immortal Hidan of the Akatsuki. Though the exact reason for Kishimoto changing Itachi’s design is never given, fans are almost surely grateful things turned out the way they did. Within the world of Naruto, Itachi Uchiha possesses one of the most iconic designs and his current look is absolutely an upgrade from his earlier incarnation.
Source: Naruto Secret: Scroll of Formation Character Official Databook