He discovered science fiction in his teens. The genre was just beginning to take shape. There were scientific romances and adventure stories from older generations—Poe and Verne—as well as stories along those lines being produced by contemporary authors—Wells, Burroughs, Doyle—but it was Hugo Gernsback who was consolidating science fiction into a recognizable genre. His Amazing Stories came out in 1926. At MIT, Campbell wanted to buy a car, but his father refused, and so he turned to writing stories for the new science fiction market, and found himself successful enough. He finished MIT (did he?) but also continued writing under a couple of names.
His John W. Campbell byline went with stories of what he called, in a clever spoonerism, “thud and blunder,” tales of galactic derring-do and adventure. Under a pseudonym, Don A. Stuart, he worked out more thoughtful, though also deeply pessimistic, narratives. These often lacked a robust plot, but made of for it with their considerations of the limits of science and human knowledge. He also used the names Karl van Campen and Arthur McCann.