Ferguson was the eldest of two children of W. Thomas Ferguson, a native Scottish merchant, and his American wife Annie Boynton. He grew up in his native Ferndale. As a young man, he became connected with Gilmor Brown, the famed founder and Director of the Pasadena Community Playhouse, and became one of its first Directors. He directed as well as acted in many plays there. He made his film debut in 1939 in Gambling on the High Seas (released in 1940), and appeared in nearly 200 feature films and hundreds of TV episodes subsequently.

In 1948, he appeared as "McDougal"- the quickly agitated owner of "McDougal's House of Horrors"- in the Universal comedy/horror film "Abbott & Costello Meet Frankenstein". In 1952, he had an uncredited role as a jailer in the film Ma and Pa Kettle at the Fair. He also appeared in Episodes 149, 173 and 178 of "The Lone Ranger".

Even before My Friend Flicka and Lassie, Ferguson appeared in five episodes as "Murdock" in the 1953-1954 ABC sitcom, The Pride of the Family, starring Paul Hartman, Fay Wray, Natalie Wood and Robert Hyatt. He also appeared in an episode of Jackie Cooper's NBC sitcom, The People's Choice. He was cast as Doc Spooner in the 1959 episode "Wolf" of the ABC/Warner Brothers western series, Sugarfoot, with Will Hutchins in the title role.

He guest starred in all three of Rod Cameron's crime series, City Detective, (1955), State Trooper (in the 1957 episode "No Blaze of Glory", the story of a presumed arson case with a surprise ending, with Vivi Janiss as his wife) and COronado 9 (1960). He was a guest star in the final season of ABC's Leave It to Beaver sitcom in 1963.

Ferguson played three different characters on The Andy Griffith Show, two different characters on Petticoat Junction, four different characters on Bonanza, four different characters on Perry Mason (including three episodes as a sheriff), and four different characters on the ABC/WB western, Maverick. He guest starred on other series, including the syndicated Rescue 8, Whirlybirds, and The Everglades; NBC's The Restless Gun, Riverboat, Overland Trail, National Velvet, and Mr. Novak; ABC's The Real McCoys, The Rifleman, The Alaskans, Target: The Corruptors, The Asphalt Jungle, and Mr. Smith Goes to Washington, and CBS's General Electric Theater (hosted by Ronald W. Reagan), and The Texan, starring Rory Calhoun. Ferguson appeared twice in 1956 as Henry Murdock (a name similar to his character in The Pride of the Family) on the syndicated western-themed crime drama, Sheriff of Cochise.

Ferguson portrayed Roy Bean, justice of the peace in Langtry, Texas, in the 1959 episode "Law West of the Pecos" of the ABC/WB western series, Colt .45, starring Wayde Preston. The Judge Bean role had been filled by Edgar Buchanan in a 1956 syndicated western series. In the Colt .45 episode, Lisa Gaye portrayed June Webster, and Douglas Kennedy was cast as Jay Brisco. Ferguson had also appeared as Todd Slater in the 1958 Colt .45 segment, "Rare Specimen".

In 1960, Ferguson portrayed Judge Lloyd "Ol' Hang 'em By The Neck" Pomeroy in "Riot At Arroyo Seco" on the syndicated television series, Cheyenne (S4:E9) in which he sees through an entire town's deception and dismisses murder charges against Sheriff Body (Clint Walker) who had been forced to kill the leader of a lynch mob in order to protect a prisoner.

On June 3, 1961, Ferguson was cast as Governor Lew Wallace of the New Mexico Territory in "The Great Western" of the NBC western series, The Tall Man, starring Barry Sullivan as Sheriff Pat Garrett and Clu Gulager as Billy the Kid. In the story line, as Wallace visits Lincoln, New Mexico, Sheriff Garrett tries to keep down brawling in the cantina owned by Big Mamacita (Connie Gilchrist), who is the grandmother of the governor's young aide.

In the 1963-1964 season, Ferguson was cast in the recurring role of Judge Gurney in the NBC/Warner Brothers western series Temple Houston, with Jeffrey Hunter as an historical person, the frontier Lawyer Temple Lea Houston, youngest son of Sam Houston. Jack Elam and Mary Wickes were other secondary characters. The series ended after twenty-six weeks.

Ferguson died in Los Angeles of cancer on September 12, 1978.