Born in Thunder Bay, Ontario, Canada. While a boy, his family moved to the United States and Walton became a U.S. citizen. He received a bachelor’s degree in radio engineering from Washington University.
From early fan letters, Walton began publishing fiction in the mid-1930s and went on to an extremely prolific career, most of which involved pseudonyms. A letter he wrote to Damon Knight in 1937 has been described by Harry Warner Jr. as the impetus for the article "Unite--or Fie!" which sparked the foundation of N3F.
In January 1942, he enlisted in the U.S. Navy. Despite seeing combat throughout the Pacific, Walton managed to continue submitting stories to the pulps which were still being published.
Following the war, Walton settled first in Moscow, Idaho, where he founded a writing group which would eventually become the “Moscow Moffia.” By 1950, Walton was living in Madison, Wisconsin. In 1956, Walton moved to Waltham, Massachusetts, his last known address. Walton's earliest works, from "The Green Death" to "Raiders from Beyond Antarres" (1938) were derivative space operas, similar to, but lesser in quality than, the works of E.E. "Doc" Smith, Edmond Hamilton, and Ray Cummings. All of his works, with one exception, were science fiction. The only time he strayed from the genre was the publication in Unknown in 1939 of the story “Rats in the Belfry.” Although John W. Campbell, Jr. loved the story and it received excellent comments, Walton is known to have viewed it as the worst thing he had ever written.
In The Founders of the Future, science fiction historian Robert Rede claimed that Walton was killed in a car accident in early 1957 and that his last four stories were published posthumously. Rede points to police records from Waltham, Massachusetts, where Walton was living at the time. However, Sam Moskowitz claims that he spoke to Walton in 1962. According to Moskowitz's story, Walton turned his back on writing science fiction to take a job working for the government, first on the Dyna-Soar project and later on Mercury.
At a Windycon, Fred Pohl described his interactions, always via mail, with Walton, noting that he was extremely reclusive. According to Pohl, The only member of the science fiction community who actually claims to have seen him was Clifford Simak, who once staked out the post office in Madison where Walton maintained a PO Box.