Itachi : The Akatsuki was a group of powerful S-ranked rogue ninja who worked as mercenaries, but their true goal was to capture the Tailed Beasts in order to change the world. Aside from Zetsu, every single member of the group was a Kage-level ninja, which means that they were both strong and smart, but when it comes to pure intelligence, some members were smarter than others.
Like everyone else, Itachi has made his fair share of mistakes, and most of them revolved around his love for Konoha and Sasuke. After killing his clan to prevent a coup, Itachi joined the Akatsuki in order to look like a real criminal, but he also did it to spy on the organization for the 3rd Hokage.
Itachi’s intelligence was evident from a very young age, as he scored the second-highest score on the written portion of the Chunin Exams, which is part of the reason why he became a Chunin at 10. Itachi was constantly composed, observant, methodical, and calculating, even during fights, which is why he left very little room for error.