The story goes that Mario was originally called "Jumpman." That's not what Mario creator Shigeru Miyamoto called the character.
"Well, I called him 'Mr. Video'," Miyamoto said in the recent Iwata Asks feature on Nintendo's official site. "My plan was to use the same character in every video game I made."
Miyamoto was confident that he had come up with a solid character. "That's why I decided a solid, imposing name like 'Mr. Video' would work best," he added. "But thinking back, I don't think I should have gone with that name." Good thing someone at Nintendo of America came up with the name Mario. "If he had been called "Mr. Video," he might have disappeared off the face of the earth."
The idea to put Mario in multiple games wasn't simply clever branding on Miyamoto's part: he was influenced by Hollywood film director Alfred Hitchcock. "I thought the way Hitchcock cropped up in all the films he directed was really cool!" Miyamoto was also influenced by manga artists like Osamu Tezuka (Astro Boy) and Fujio Akatsuka (Tensai Bakabon), who put their characters in multiple works. And now you know!
Iwata Asks: New Super Mario Bros. Wii [Wii.com]