Coburn served in the military in the First World War. He later spent time as a cowboy and a surveyor, before becoming a full-time writer in the 1920s.
Coburn began his career with Western stories in general fiction pulp magazines such as Adventure and Argosy. Later Coburn moved on to pulps specializing in Westerns, including Western Story Magazine, Lariat Story Magazine, Ace-High Western and Frontier Stories. He often wrote for the Fiction House pulp magazines Dime Western and Star Western who promoted Coburn as "the Cowboy Author".
Coburn was enormously prolific; Flanagan states Coburn wrote almost two million words of fiction over a thirty year period. Coburn was so popular that eventually, two pulp magazines - Walt Coburn’s Western Magazine and Walt Coburn’s Action Novels were issued, consisting mainly of reprints of Coburn's work.
After the pulps ended in the 1950s, Coburn switched his focus to writing paperback originals.
- The Ringtailed Rannyhans (1927)
- Mavericks (1929)
- Barb wire (1931)
- Walt Coburn's action novels; four western novels (1931)
- Law Rides the Range (1935)
- Sky-Pilot Cowboy (1937)
- Pardners of the Dim Trails (1951) (vt: Tough Texan)
- The Way of a Texan (1953)
- Drift Fence (1953)
- The Burnt Ranch (1954)
- Gun Grudge (1955)
- Wet Cattle (1955) (vt: Violent Maverick)
- The Square Shooter (1956)
- Border Jumper (1956)
- The Night Branders (1956)
- One Step Ahead of the Posse (1956)
- Cayuse (1956)
- Stirrup High (1957)
- Fear Branded (1957)
- Horsethief Trail (1957)
- Spiderweb Ridge (1958)
- Beyond the Wild Missouri (1958)
- Buffalo Run (1958) (vt: Fast Gun)
- Free Rangers (1959)
- Dark and Bloody Ground (1960)
- Guns Blaze on Spiderweb Range (1961)
- Invitation to a Hanging (1963)
- Ramrod (1963)
- Branded (1963)
- Sons of Gunfighters (1963)
- The Kansas Killers (1966)
- Feud Valley (1969)
- The Renegade (1969)
- La Jornada (1971)
- Sleeper's Mark (1990)
- Showdown Mesa (1992)
- Coffin ranch : a western trio (1998; edited by Jon Tuska).
- Pioneer Cattleman in Montana: Story of the Circle C Ranch (1968)
- Western Word Wrangler (1973)
- John D. Flanagan, "Coburn, Walt", in Twentieth Century Western Writers, edited by Geoff Sadler. St. James Press, 1991, ISBN 0-912289-98-8 , (pp. 129-34)
- Lee Server, "Coburn, Walt" in Encyclopedia of Pulp Fiction Writers. Facts on File, 2002 ISBN 978-0-8160-4578-5 (pp. 65-66)
- Jon Tuska, The Western Story: A Chronological Treasury, University of Nebraska Press, 1999, ISBN 978-0-8032-9439-4 (p.xxviii).
- Jon Tuska, Star Western, Gramercy Books, 1995, ISBN 0-517-14688-6 (p.132).