Born in La Harpe, Illinois to Elbert and Ann Williams Soule (descendants of three Mayflower passengers), Olan left Illinois at the age of seven and arrived in Des Moines, Iowa, where he lived until he was seventeen. He then launched his theatrical career by joining Jack Brooks’ tent show in Sabula, Jackson County, in eastern Iowa. After leaving the tent show, Soule appeared on stage in Chicago for seven years before moving to radio in 1933, including a stint on Chandu the Magician (1935–36). On radio he performed for eleven years in the daytime soap opera Bachelor’s Children. Beginning in 1943, he did lead male characters on radio’s famed The First Nighter Program for nine years. Listeners of First Nighter who met Soule in person were often surprised, since his slight 135-pound frame did not seem to match the voices he gave to his characters. From 1941 on, Soule had the role of L. William Kelly, SS-11, the second in command of the Secret Squadron on the Captain Midnight radio adventure serial. When Captain Midnight became a television series in the 1950s, Soule was known as SQ-3, behind Captain Midnight himself and Ichabod Mudd “with two D’s”. He also has a regular part on Lee Hansen’s 1970’s and 1980s science fiction radio drama Alien Worlds.

Concluding his nine-year run on First Nighter, Soule moved to Hollywood, where he did films and television, building a reputation as a reliable character actor. He was best known as Mr. Krull, a boarding house resident in The Day The Earth Stood Still. He appeared on many television series: The Donald O’Connor Show (as a semi-regular), Captain Midnight (as scientist Aristotle “Tut” Jones), I Love Lucy, several appearances as a hotel clerk and choir director on The Andy Griffith Show, and a semi-regular role as real-life LAPD criminalist Ray Murray on Dragnet. He also made six appearances on Perry Mason, mostly as a court clerk, but also as a bank employee and water company official. The list of Soule’s supporting and starring roles is long. Some include The Real McCoys, Mister Ed, City Detective, Behind Closed Doors, Dante, Harrigan and Son, Hennesey, State Trooper, One Step Beyond, The Restless Gun, The Rebel, Wanted: Dead or Alive, The Twilight Zone, The Untouchables, Bewitched, Pete and Gladys, The Addams Family, The Munsters, Johnny Ringo, Rawhide, Gunsmoke, Happy, Bonanza, The Jean Arthur Show, Laramie, The Monkees, Mission: Impossible, The Six Million Dollar Man, Fantasy Island, Little House on the Prairie, Dragnet, Dallas and Simon & Simon. He was the only actor who performed on both the Captain Midnight radio and television shows.

Soule is remembered by many for providing the voice of Batman in several animated series. He first performed as the Caped Crusader on the 1968 Filmation-produced The Batman/Superman Hour. He reprised his role as Batman on The Adventures of Batman, The New Scooby-Doo Movies, Sesame Street (1970), Super Friends (1973), The All-New Super Friends Hour, Challenge of the SuperFriends, The World’s Greatest Super Friends and Super Friends (1980). He appeared as a newscaster on the live-action Batman television series (in “The Pharaoh’s in a Rut”) with his Super Friends successor Adam West. Although Soule eventually gave back the Batman mantle to the man who portrayed him in live-action, he continued to contribute in the Super Friends: The Legendary Super Powers Show series, providing the voice of Professor Martin Stein, mentor and subconscious of fledgling hero Firestorm. On February 1, 1994, Soule died of lung cancer in Corona, California, at the home of his daughter, Jo Ann, and son-in-law, Dr. David Henriksen. He was eighty-four years old.