Gulick was born in Kansas City, Missouri. According to his autobiography, his grandmother wanted him to be named after his father, as Grover Cleveland Gulick, Jr.; but his mother resisted fiercely, and they eventually compromised with Grover C. (only) Gulick, "with my Mother saying I could choose my own middle name when I became old enough to do so." He later acquired the nickname 'Bill'.
Gulick had numerous short stories and 20 novels published, of which three have been made into movies. His book Snake River Country won the 1971 Pacific Northwest Booksellers Award as Best Non-fiction Book.
- 1955 – The Road to Denver, short story published in the Saturday Evening Post
- April 4, 1942 – The Saga of Mike Shannon, short story published in Liberty Magazine
- 1950 – Bend of the Snake, novel
- 1952 – A Drum Calls West, novel
- 1954 – A Thousand for the Cariboo, novel
- 1958 – The Land Beyond, novel
- 1958 – Showdown in the Sun, novel
- 1961 - Shaming of Broken Horn, novel
- 1962 – The Moon-Eyed Appaloosa, novel
- 1963 – Hallelujah Trail, novel
- 1966 – They Come to a Valley, novel
- 1969 – Liveliest Town in the West, novel
- 1971 – The Country Club Caper, novel
- 1971 – Snake River Country, non-fiction
- 1979 – Treasure in Hell's Canyon, novel
- 1981 – Chief Joseph Country: Land of the Nez Percé, non-fiction
- 1988 – Northwest Destiny: A Trilogy, Distant Trails 1805–1836; Gathering Storm 1837–1868; Lost Wallowa 1869–1879, novel
- 1990 – Roadside History of Oregon, non-fiction
- 1996 – A Traveler's History of Washington, non-fiction
- 1997 - Roll On, Columbia: To the Pacific : A Historical Novel (To the Pacific/Bill Gulick, Bk 1), historical fiction 
- Hallelujah Trail (1965), based on the novel Hallelujah Trail, aka 'John Sturges' The Hallelujah Trail
- Hotel de Paree (1960), 1 episode: "Sundance and the Greenhorn Trader"
- The Road to Denver (1955), based on a Saturday Evening Post story
- Bend of the River (1952), based on the novel Bend of the Snake
- Porter, Andy (29 October 2013). "Noted western author Bill Gulick dies". Yakima Herald. Archived from the original on 9 December 2013. Retrieved 9 December 2013.
- Roadside History of Oregon, Gulick, Bill, 9780878422524, Mountain Press Publishing, 1991
- Gulick, Bill (2006). Sixty-Four Years as a Writer. San Francisco: Ignatius Press. ISBN 0-87004-453-2.
- William Gulick. Internet Movie Database. 2010-05-28. URL:https://www.imdb.com/name/nm0347738/. Accessed: 2010-05-28. (Archived by WebCite at https://www.webcitation.org/5q3hHrKZJ)
- Gulick, Bill (1996). A Traveler's History of Washington. San Francisco: Ignatius Press. ISBN 0-87004-371-4.
- Roll On, Columbia: To the Pacific : A Historical Novel (To the Pacific/Bill Gulick, Bk 1), Amazon.com, https://www.amazon.com/dp/0870814257