[4] Born in Big Spring, Texas, to Mike Fronabarger and his wife, Mary Edith, he started his film career performing in choruses and working as a stunt double, then graduating into larger roles, mostly in B pictures.

[3] O'Brien acted in the Metro-Goldwyn-Mayer comedy short film series Pete Smith Specialties.

[4] In 1933, O'Brien also had a small dancing part with Bebe Daniels in the Busby Berkeley musical 42nd Street.

O'Brien portrayed a frantic drug abuser in the 1936 anti-drug film Tell Your Children (better known under its reissue title, Reefer Madness).

[5] He appeared in low-budget Westerns, such as Producers Releasing Corporation's Texas Rangers series, billed as "Tex O'Brien".