The Truth About All Might's Symbolism In My Hero Academia
"My Hero Academia" is not your typical superhero story. The anime, originally created by Kōhei Horikoshi, is set in a world where 80% of the population develop a unique form of superpowers called "Quirks" and what people decide to do with their powers is what ultimately leads to superheroes and villains. The story follows a boy named Izuku Midoriya who strives to become the world's Number One superhero although he was born without a Quirk. That is, until he meets his idol, the great All Might, who passes along his One For All Quirk to Izuku, putting him on his path to superhero success.
All Might was considered to be the world's Number One superhero until a previous battle with a villain left him unable to use his quirk for extended periods of time. Since he is unable to use his quirk, he now goes by Toshinori Yagi and appears to be much more straggly and thin than in his hero form. In his heyday, All Might was considered to be the world's "Symbol of Peace" and with his blond hair, super buff body, and red, white, and blue color scheme, it's obvious what All Might also symbolizes.
All Might is a nod to a famous American superhero
In the series, All Might begins his superhero career in America while he is studying abroad and spends a considerable amount of time learning the western culture. That is where he developed his initial costume, dramatic mannerisms, and outgoing personality and it's all modeled after the most famous superhero of all time, Superman.
All Might's ties to western superhero culture is not only evident in his appearance and personality, but also in his superhero moves. As he winds up to socker punch his enemies, All Might will shout "Texas Smash!" "Carolina Smash!" or another attack name modeled after U.S. places. In a Reddit thread, user wub_addicted explained the reasoning behind this: "His whole character is an allusion to Superman. The way he looks, the way he's seen, the way everyone feels about him. That's just another reference to the character that inspired him. Superman is American, of course Horikoshi would do something with that."
All Might could be a political symbol
Aside from his obvious connection to Superman, another Reddit thread theorizes that All Might could serve as a more political symbol of the U.S. and its relations to Japan. User WhimsicalWyvern wrote: "...the US, like All Might, is extremely powerful, and defeated a very powerful nemesis in the past (Imperialism in Japan) and built up / protected Japan (reconstruction after WW2, trade relations, US taking over defense of Japan), but there are new threats rising (China), and US (economic) power isn't nearly as strong as it used to be (relatively speaking). Now Midoriya and his friends (Japan... and allies in SE asia / Oceania?) needs to take up the mantle of Symbol of Peace and learn how to do without All Might (expansion of the NDF?)"
WhimsicalWyvern also said "Or maybe I'm just reading way too much into things and All Might just likes the US." Many users were quick to agree with this sentiment and one user Jantripp responded "I think it's an interesting idea. Whether or not Horikoshi intended that, the events of WW2 have shaped a lot of Japanese popular media. Just look at Godzilla for a prime example of that."
Whether or not All Might symbolizes a deeper meaning related to a post World War II Japan, there's no doubt All Might serves as a reminder of American superhero culture.