James Ellison Smith was born in 1910 in Guthrie Center, Iowa, and grew up on a ranch in Valier, Montana, where he developed skills that would serve him well as a movie cowboy. His family relocated to Los Angeles when he was a young man, and it was there that he first became interested in the theatre. Ellison briefly studied at the Pasadena Playhouse, then traveled to New York, where he possibly appeared in minor roles with the Moscow Art Theatre.
After returning to California, he was spotted by a Warner Bros. talent scout at a production of the Beverly Hills Theatre, leading to a series of small parts for Warners and MGM. Ellison's big break came when he landed the role of Johnny Nelson, Hopalong Cassidy's sidekick, in Paramount's popular series. Although a supporting player, his name was oddly billed alongside William Boyd's, reportedly due to the character's prominence in the Hopalong Cassidy book series.
Ellison's performance in the Hopalong Cassidy films caught the attention of Cecil B. DeMille, who cast him as Buffalo Bill Cody in his epic Western, The Plainsman, opposite Gary Cooper. DeMille reportedly disliked Ellison's performance, allegedly attempting to ensure he would never receive another significant role.
In the late 1930s and 1940s, Ellison continued to appear in romantic leads, partnering with stars like Maureen O'Hara, Lucille Ball, James Stewart, and Ginger Rogers in films such as They Met in Argentina, Next Time I Marry, Vivacious Lady, and I Walked with a Zombie. In 1950, he returned to Westerns, starring alongside Russell Hayden in a series of 11 films as frontier lawmen Lucky and Shamrock.
Although best remembered as Hopalong Cassidy's first and most prominent sidekick, Ellison is also notable for his work in a variety of films, including the cult horror classic I Walked with a Zombie. In the late 1950s, he retired from acting and became a successful real estate broker. James Ellison passed away in 1993 at the age of 83, following a fall that broke his neck.
Throughout his life, Ellison was married twice, first to Gertrude Durkin, with whom he had two children, Durk and Trudy, and then to Lois Bretherton, whom he married in 1972 and remained with until his death.