Rex Beach was born in Atwood, Michigan to a prominent family and pursued a career as a lawyer before being drawn to Alaska at the time of the Klondike Gold Rush. After five years of unsuccessful prospecting, he turned to writing.

His first novel, The Spoilers, was based on a true story of corrupt government officials stealing gold mines from prospectors, which he witnessed while he was prospecting in Nome, Alaska. The Spoilers became one of the best selling novels of 1906.

His adventure novels were immensely popular throughout the early 1900s. Beach was lionized as the "Victor Hugo of the North," but others found his novels formulaic and predictable. Critics described them as cut from the "he-man school" of literature: stories of "strong hairy men doing strong hairy deeds." Alaska historian Stephen Haycox has said many of Beach's works are "mercifully forgotten today."

One such potboiler, The Silver Horde (1909), is set in Kalvik, a fictionalized community in Bristol Bay, Alaska, and tells the story of a down on his luck gold miner who discovers a greater wealth in Alaska's run of salmon (silver horde) and decides to open a cannery. To accomplish this he must overcome the relentless opposition of the "salmon trust," a fictionalized Alaska Packers' Association, which undercuts his financing, sabotages his equipment, incites a longshoremen's riot and bribes his fishermen to quit. The story line includes a love interest as the protagonist is forced to choose between his fiance, a spoiled banker's daughter, and an earnest roadhouse operator, a woman of "questionable virtue." Real life cannery superintendent Crescent Porter Hale has been credited with being the inspiration of The Silver Horde but it's unlikely Beach and Hale ever met.

After success in literature, many of his works were adapted into successful films; The Spoilers became a stage play, then was remade into movies five times from 1914 to 1955, with Gary Cooper and John Wayne each playing "Roy Glennister" in 1930 and 1942, respectively.The Silver Horde was twice made into a movie, as a silent film in 1920 starring Myrtle Stedman, Curtis Cooksey and Betty Blythe and directed by Frank Lloyd; and a talkie in 1930 that starred Jean Arthur, Joel McCrea and Evelyn Brent and was directed by George Archainbaud.

Beach occasionally produced his films and also wrote a number of plays to varying success. In 1949, two years after the death of his wife Edith, Beach committed suicide in Sebring, Florida at the age of 71. In 2005, when the home Beach lived in was remodeled, a bullet was found in the wall, believed to be the bullet that ended his life.

Beach served as the first president of the Rollins College Alumni Association. He and his wife are buried in front of the Alumni house.

In 1904 he was a member of the American water polo team which won the silver medal in the St. Louis Games.