America is a cheerful, energetic, yet somewhat conceited young man who is obsessed with heroes, justice, and freedom. He has the habit of sticking his nose into everyone else's business, which causes him to have difficulty making friends. He loves hamburgers and junk food, to the point of an obsession, and can even eat strange and inedible things due to inheriting England's sense of taste (or lack thereof).

America is also known for not being aware of how "the atmosphere" is when he is around others (which, at one point, he was told to read it), but it has been noted that it is not that he lacks the ability to "assess the situation", he simply chooses not to. His profile states that his hobbies are sports, games, and making movies, but he also enjoys watching movies specifically of the horror genre. On multiple occasions, he has forced Japan to watch movies that he calls "Too freaking scary!" because they are about ghosts and paranormal activity. Japan gives him zombie video games to come over his fear of ghosts. Furthermore, in the side-story Black Ships Have Come, in introducing himself to Japan, he states that his hobbies are "quick-draw, archaeology, and adventures" (which is translated to Japan as America's hobby being lechery).

He possesses an abnormal amount of strength, shown even as a child by easily swinging a full-grown buffalo around, and has been once seen running around dragging a heavy Rolls Royce that belong to England with one hand behind him for an hour in order to ask permission to borrow it. In the NotoSama 6 game, America was able to stop a car with the heel of his foot.

America is shown to be ignorant of the geography outside his own home, believing that maps of the United States constitute the "world map" and believes that he can simply get to other countries by car travel. He is shown becoming concerned about his weight in the strip Supersize You! and it is mentioned that he has invented strange diet machines as well as becoming obsessed with exercise which has caused him to become paranoid about his rising weight, as he is unaware of his building muscle. Aside from being afraid of ghosts, scary movies, and weighing scales, he also fears marmite. As America is obsessed with heroes and happy endings, he hopes that his future will be that way.

Though he is friends with a space alien named Tony, he does not believe in England's magical friends, fairies, or unicorns, except on Halloween.