His most famous work, "The Curse of Capistrano" (1919), serialized in All-Story Weekly, introduced Don Diego Vega, a nobleman who secretly defends the people of Spanish California as the sword-wielding outlaw Zorro. The character gained lasting fame through the 1920 film adaptation "The Mark of Zorro," starring Douglas Fairbanks, which launched an enduring franchise in film, television, and literature.
Beyond Zorro, McCulley created numerous pulp heroes and characters, including the crime-fighter Black Star, the detective known as The Spider, the witty pickpocket Thubway Tham, and the western cowboy Jim Hatfield. Although Zorro defined his legacy, McCulley rarely revisited the character, preferring to explore new creations for the pulp market. He died in Los Angeles in 1958, leaving a lasting influence on the superhero and adventure genres.