Squall has appeared in several other games, including Chocobo Racing, Itadaki Street Special, and the Kingdom Hearts series as the older mentor-like figure named Leon (レオン, Reon).

To ensure players understand Squall's silent attitude, Kazushige Nojima made the character's thoughts open to them.

Squall had a mixed reaction from critics, some of whom judging him poorly in comparison with other Final Fantasy heroes due to his coldness and angst, and others praised his character development.

[3] When asked about what is one thing Kitase would change about the game, he mentioned the FH concert where Rinoa Heartily mocks Squall by mimicking his mannerisms and he raises his hand at her and she dodges.

[3] In the original Japanese game, Squall has a tendency to respond negatively to other characters' comments by using sarcastic remarks like "well, excuse me".

[13] After objections from Kitase, Nomura made the character more masculine and added a scar across Squall's brow and the bridge of his nose to make him more recognizable similar to Cloud Strife's striking spiky hair from Final Fantasy VII, leaving its cause up to scenario writer Kazushige Nojima.

Event planner Jun Akiyama persuaded Nomura to change Squall's name to Leon in order to make his introduction more surprising to the players as he is first mentioned in a letter from Mickey Mouse.

[18] Leon's design was revised to be more effeminated using the original sketches from Final Fantasy VIII that only appeared in the game's logo.

[32] He gradually warms and his detachment from his companions is later revealed to be a defensive mechanism to protect himself from the emotional pain he suffered when he and his older step sister were separated.

[35] Squall appears as a non-playable character in Kingdom Hearts, in which he wears a short leather jacket with red wings on the back and a Griever necklace.

Squall takes the name Leon as an alias because he is ashamed of not protecting those he loved from the Heartless when his home world the Radiant Garden was consumed by darkness.

[39] In the sequel Kingdom Hearts II game, he works with his friends to restore their world alongside Sora while facing the army of Heartless creatures used by the villains, Organization XIII.

He returns with his Kingdom Hearts as downloadable content (DLC) in Dissidia 012 where Squall is defeated by Kain Highwind from Final Fantasy IV who wants him to stop from fighting Chaos' mannekins army.

Jack Patrick Rodgers of PopMatters said Squall's cynicism and frustration with those around him made him a strong character but "coldly inhuman".

[72] While noting that Squall manages to become a better person, the changes are minimum and the idea of him being able to save the world comes across as "cringe comedy" due to its characterization.

GamesRadar's Brett Elston criticized it, comparing it with the romance from Attack of the Clones,[74] but in a different article, he commented that "Squall and Rinoa are at the heart of it all" even if they do not properly develop.

[75] According to Ryan Woo of Complex, the problem with the romance was it because it was mostly one-sided from Rinoa's side until the latter parts of the game where Squall's development makes it come across as forced.

[77] On a more positive view, the website called Squall and Rinoa the best couple created by Square Enix, noting the differences between them and that their relationship is the first in the series to drive the plot of a game.

[85] Comic Book Resources lamented how Squall and the rest of the Final Fantasy characters became cameos in Kingdom Hearts III and the player never gets the chance to fight against them.

[86] VentureBeat said that while Kingdom Hearts offered Squall a more passable backstory, he still lacked development to the point he is often overshadowed by Laguna not only in his original appearance but also Dissdia.

[87] In retrospect, while Fanbyte found Leon more sexually appealing than Squall, the writer felt that his new backstory made the character unlikable as he broods even more than in his original game.

[90] GameRant believes David Boreanaz was chosen for Squall's role due to voicing a similar brooding anti-hero, Angel, in Buffy the Vampire Slayer with Doug Erholtz providing a nearly identical performance in following games.

[91] Hideo Ishikawa's performance as Squall was highlighted as popular within even if he never got the chance to properly voice him in his original game as said by fans in Animate Times.