Harry Bates was born Hiram Gilmore Bates III on October 9, 1900 in Pittsburgh, Pennsylvania..

Harry Bates began working for William Clayton in the 1920s as the editor of adventure pulp magazines. When Clayton proposed a period adventure magazine, Bates suggested several alternatives that he felt would be easier to edit and Astounding Science Fiction was the result. Bates, who was not a fan of science fiction, edited the magazine from its inception in January 1930, until March, 1933, when Clayton went bankrupt and the magazine was sold to Street and Smith. During that time, he edited other magazines for Clayton, including Strange Tales, calculated to compete with Weird Tales.

Bates found the science fiction stories of the time to be poorly written: "Amazing Stories! Once I had bought a copy. What awful stuff, I'd found it! Cluttered with trivia! Packed with puerilities. Written by unimaginables! But now at the memory I wondered if there might be a market for a well-written magazine on the Amazing themes." Bates wrote that the "science fiction of the early writers had little relation to science of the scientists." What science fiction writers did was to "exptrapolate" and not "relate" because "almost all of what is called science fiction is fantasy and nothing else but."

Bates recalled his role in the creation of Astounding in 1964: "Long ago I was a party to the genesis of a magazine which persisted through thirty years and thirty millions of words. ... Astounding was a living being. I served it in its infancy and childhood, Orlin Tremaine brought it through youth and adolescence, John Campbell guided it through adulthood and maturity."

Clayton was willing to pay four times more than the rates offered by Hugo Gernsback's rival Amazing Stories. Bates had a different view of science fiction than Gernsback. Bates felt that the science needed to be exciting but not necessarily accurate and that story and pacing were more important, thus starting science fiction's change from its "pulp" origins.

Using the pseudonyms Anthony Gilmore and H.G. Winter, Bates and his assistant editor Desmond Winter Hall collaborated on the "Hawk Carse" series and other stories. In 1952, the Hawk Carse stories were collected in Space Hawk: The Greatest of Interplanetary Adventurers. Bates's most famous story is "Farewell to the Master" (Astounding, October 1940), which was the basis for the classic science fiction movie filmed in 1951 as The Day the Earth Stood Still and the 2008 remake, as well as the 1973 Marvel Comics Worlds Unknown series adaptation.

Bates recalled the creation of the Hawk Carse science fiction series in Requiem for Astounding (1964): "From the beginning I had been bothered by the seeming inability of my writers to mix convincing character with our not-too-convincing science; so after nearly two years, with the double hope of furnishing the writers an example of a vivid hero and villain and my readers a whopping hero versus villain, I generated the first Hawk Carse story."

Two novellas by Bates appeared in Gernsback's Science-Fiction Plus, edited by Sam Moskowitz. "The Death of a Sensitive" (May, 1953) was ranked by Moskowitz as the best story he ever ran in the magazine. Both Gernsback and Moskowitz, however, wanted changes in "The Triggered Dimension" (December, 1953). Bates agreed to make the changes and arrived at 25 West Broadway to make the requested cuts and revisions.

That same year Moskowitz began teaching what is believed to be the first college course on science fiction at City College. Bates had agreed to speak as a guest lecturer at the first class. In a move of calculated retaliation for the cutting of his story, however, Bates intentionally did not show up for the class, putting Moskowitz in an awkward spot. Moskowitz recalled the aftermath:

Seven years later, I received a letter from Harry Bates dated October 2, 1960. In essence, it revealed that Bates was now totally disabled due to progressive arthritis and was trying to get early Social Security at 60. He had a doctor's statement that he was suffering from that condition at present, but they wanted proof that it was progressive and prevented him from writing stories for income. He asked if I would be willing to supply a statement that he had written stories for me with the greatest difficulty. He didn't know if he had ever mentioned it to me, but any validation would help. It so happened that he had shown me his swollen knuckles in 1953, but beyond that, I had a letter from him describing the difficulty, written earlier that year. I mailed him back the letter, for which I still had the dated envelope, and he got his Social Security...his only income for the next 20 years! Christmas of 1962 I received a card from him on which he scrawled: "I ain't mad at you no more."

In 1964, Bates contributed an introductory essay, Editorial Number One, "To Begin", along with John W. Campbell, to A Requiem for Astounding by Alva Rogers, which examined the history of the pioneering science fiction magazine Astounding.

Harry Bates died in September, 1981, at the age of 80.

In 1951, Twentieth Century Fox released the movie The Day the Earth Stood Still, which was based on the Harry Bates' 1940 short story "Farewell to the Master". The science fiction movie starred Michael Rennie as Klaatu, Patricia Neal, Sam Jaffe, and Hugh Marlowe, and Lock Martin as the giant alien robot Gort, called Gnut in the Bates' short story. The movie was directed by Robert Wise and produced by Julian Blaustein. Screenwriter Edmund H. North adapted Bates' classic short story for the screen. The movie is consistently rated by critics as one of the greatest science fiction movies ever made.

In 2008, The Day the Earth Stood Still was remade by director Scott Derrickson. The movie starred Keanu Reeves as the alien Klaatu and Jennifer Connelly. David Scarpa wrote the screenplay based on the Edmund H. North 1951 screenplay.

The critical and commercial success of the 1951 movie relied on the novel themes introduced by Bates in his short story. Instead of depicting aliens as mindless, aggressive, and conquering armies bent on taking over earth, Bates turned the tables on the cliche. Ever since The War of the Worlds (1898) by H.G. Wells, aliens were often portrayed as menacing and murderous, with a degraded moral and ethical sense. In Bates' story, aliens are the opposite, possessing a high moral character and higher ethical development. The alien Klatuu's face "radiated kindness, wisdom, the purest nobility. In his delicately tinted robe he looked like a benign god." The giant alien robot, Gnut in the short story, Gort in the film, is immensely powerful, but can exhibit sadness and gentleness. The surprise ending, where Gnut tells the journalist, who is relating the story, "You misunderstand, ... I am the master," prompts some interesting speculation about relationships between mankind and technology in the future.

While The Day the Earth Stood Still is inspired by Bates' short story, in the 1951 context of the Cold War and a nuclear stand-off the film develops the story's themes, and takes them in new directions. In the film Klaatu seeks to promote peace and to warn mankind of the dangers of science and technology when they are exploited and corrupted. The alien explains that Gort is a member of a race of all-powerful robots who were created to eliminate any civilizations who brought warfare into space. The film raises such questions as: Is man a master of science or a slave to it? Who controls whom? What is the future of mankind? Would machines control man? Could mankind transcend the lust for power and for conquest? Will there be an end to wars? These themes made the movie The Day the Earth Stood Still an enduring classic.

The 2008 version of The Day the Earth Stood Still, reflecting a major issue of its own day, takes still another direction, where the alien's concern is the destruction of the environment by mankind's activities. Earth is viewed by alien civilizations as one of a very few precious planets that are capable of supporting intelligent life, and should therefore be protected from mankind's predations.

In 1983, The Day the Earth Stood Still was inducted into the Science Fiction Film Hall of Fame as part of the Balrog Awards, which were given from 1979-1985.

Under the pseudonym of Anthony Gilmore, Harry Bates wrote the following stories in the Hawk Carse series with Desmond W. Hall, collected in Space Hawk: The Greatest of Interplanetary Adventurers (New York: Greenberg, 1952):

• "Hawk Carse", Astounding, November, 1931

• "The Affair of the Brains", Astounding, March, 1932

• "The Bluff of the Hawk", Astounding, May, 1932

• "The Passing of Ku Sui", Astounding, November, 1932

Ten years later, Amazing Stories printed the final Hawk Carse novel, written by Bates alone. This story has never been collected or reprinted.

• "The Return of Hawk Carse", Amazing, July, 1942

Harry Bates wrote the following classic science fiction short stories:

• "The Hands of Aten", with Desmond W. Hall, under the pseudonym H.G. Winter, 1931
• "The Slave Ship from Space", under the pseudonym A.R. Holmes, 1931
• "The Tentacles from Below", with Desmond W. Hall, as Anthony Gilmore, 1931
• "Four Miles Within", with Desmond W. Hall, as Anthony Gilmore, 1931
• "The Midget from the Island", with Desmond W. Hall, as H.G. Winter, 1931
• "Seed of the Arctic Ice", with Desmond W. Hall, as H.G. Winter, 1932
• "A Scientist Rises", with Desmond W. Hall, Astounding, November, 1932
• "The Coffin Ship", with Desmond W. Hall, as Anthony Gilmore, 1933
• "Under Arctic Ice", with Desmond W. Hall, as H.G. Winter, 1933
• "A Matter of Size", Astounding, April, 1934
• "Alas, All Thinking", Astounding, June, 1935
• "The Experiment of Dr. Sarconi", Thrilling Wonder Stories, July, 1940
• "Farewell to the Master", Astounding, October, 1940
• "A Matter of Speed", Astounding, June, 1941
• "The Mystery of the Blue God", Amazing Stories, January, 1942
• "The Death of a Sensitive", Science Fiction Plus, May, 1953
• "The Triggered Dimension", Science Fiction Plus, December, 1953

The short story "Farewell to the Master" appears in the following science fiction anthologies:

• They Came From Outer Space: 12 Classic Science Fiction Tales That Became Major Motion Pictures, edited by Jim Wynorski
• Isaac Asimov Presents the Great Science Fiction Stories, 1940, edited by Isaac Asimov and Martin H. Greenberg
• Machines That Think: The Best Science Fiction Stories About Robots and Computers, edited by Isaac Asimov, Martin H. Greenberg, and Patricia S. Warrick
• Reel Future, edited by Forrest J. Ackerman and Jean Stine
• Isaac Asimov’s Wonderful Worlds of Science Fiction # 9: Robots, edited by Isaac Asimov, Martin H. Greenberg, and Charles G. Waugh
• War with the Robots: 28 of the Best Short Stories by the Greatest Names in 20th Century Science Fiction, edited by Isaac Asimov