(25 October 1886 – 17 March 1937)

He was born in Choteau, Montana, and died in Hollywood, California.

A handsome, often-mustachioed silent screen villain, J. Frank Glendon (born Jonathan Frank Glendon) graduated from Montana's Wesleyan University prior to entering a stage career in the early 1910s.

By 1915, he was co-starring at Vitagraph in Los Angeles and later became a member of the Lois Weber stock company (What Do Men Want?, 1921). Glendon's acting career waned in the early '20s when he co-produced and co-starred (with stuntwoman Marilyn Mills) in a couple of inexpensive Westerns: Tricks (released 1925) and Three Pals (released 1929).

In 1935 he co-directed, with stunt expert Yakima Canutt, rodeo champion roper Montie Montana's failed claim to B-Western stardom, Circle of Death, but is today better remembered for playing the villainous Professor Beetson in the Gene Autry serial The Phantom Empire.

He appeared in 79 films between 1915 and 1936.