Walter Campbell Tetley was born to a Scottish born mother, Jessie Smith Campbell and father Frederick Tetzlaff who was born in New York of German parents.
Tetley was a precocious performer even when he really was a child, beginning at age seven performing Harry Lauder imitations. He established himself in radio, usually playing smart-aleck kids. Tetley moved to Hollywood in 1938 and acted in a number of films (he is the wisecracking messenger or pageboy in several Universal Pictures comedies), but radio was his truest metier.
Walter Tetley's perennially adolescent voice was the result of a medical condition. While this has been cited as a hormonal problem, one of Tetley's employers, Bill Scott, offered a more specific explanation. According to Scott, Tetley's mother was reluctant to give up the revenue generated from her son's busy radio career and, in Scott's words, "She had him fixed [castrated]. Walter Tetley, the world's tallest midget." Whatever the medical reason, the condition arrested Tetley's development, preventing his voice from breaking into maturity as well as preventing his further physical growth. Tetley would sound forever as though he was stranded on the bridge between boyhood and pre-teen adolescence. Combined with his excellent delivery and spot-on comic timing, he parlayed his condition into a radio career that lasted nearly a quarter of a century, with some of radio's biggest stars included Tetley in their shows, including but not limited to Fred Allen, Jack Benny, W.C. Fields and others.
Fans of vintage radio remember Walter Tetley best for two roles. He was cast to play spunky nephew Leroy on The Great Gildersleeve, beginning in 1941. (Leroy's "Ah you kiddin'?" became almost as much of a show catch-phrase as the title character's booming trill, "Leeee-rooooy!") Tetley stayed with that role for just about the entire life of that show, voicing Leroy in and out of jams from making nitroglycerin with his home chemistry set to helping Uncle Gildersleeve (Harold Peary) break out of the public library into which they got locked accidentally, after hours. The bad news: his unique appearance and true age obstructed him from playing the shorter, younger Leroy in the four Gildersleeve feature films (though he did appear in a speaking role as a bellhop in the third of those films, 1943's Gildersleeve on Broadway).
But Tetley might have been an even bigger hit beginning in 1948, when he took on a concurrent continuing role on an equally popular comedy, playing obnoxious grocery boy Julius Abruzzio on The Phil Harris-Alice Faye Show until the show's finish in 1954. (Surviving episodes that include pre-air audience warmups by Phil Harris usually included Harris alluding to Tetley as "the kid who steals the show every week"—even though Tetley was almost 40 years old when the Harris-Faye show ended production.) Julius combined an obsession with getting the better of his clumsy elders Phil and Remley to an unconcealed crush on Alice and was as much a fixture on the show as Harris's in-character malapropping vanity and Faye's tart but loving earthiness. He also played minor roles, such as a boy in a drugstore in the radio drama Dr. Christian (1937–1939). An example is in the "Dog Story" episode.
"I wondered what a radio show would be like if the audience could see the actors on stage," Tetley was quoted as saying once about his radio work. "But then they couldn’t be allowed to read scripts. It would be like a movie. That wouldn’t be any good. Radio would then be the same as movies." To the same interviewer, Tetley admitted that adulthood in the body of a child troubled him enough, finding it difficult for many years to make adult friends or even to assert himself to his own family. But he finally made peace with the dichotomy, accepted himself, and distinguished between his meal ticket and his self successfully.
Tetley's career was not quite finished when the Harris-Faye show's run ended. He would become familiar to a new generation as the voice of Sherman, the nerdy, freckled, bespectacled boy sidekick of time-traveling dog genius Mr. Peabody, in the "Peabody's Improbable History" segments of The Rocky Show (also known as The Bullwinkle Show), which made its debut in 1959.
Tetley also worked for Capitol Records in the 1950s, providing an array of juvenile voices for the label's spoken-word and comedy albums, including Stan Freberg Presents The United States of America Volume One The Early Years. His Gildersleeve co-star, Harold Peary, had made three albums for Capitol a decade earlier, telling children's stories Gildersleeve-style. In 1973 Tetley made an appearance on the Rod Serling radio series, "Zero Hour". He can be heard in the "Princess Stakes Murder" episodes beginning the week of November 19.
In 1971, after several more years' voiceover work, Tetley was seriously injured in a motorcycle accident and used a wheelchair for the rest of his life. Numerous sources have suggested Tetley may have lost his southern California home in the same period and lived out his days in a trailer. He died in 1975 at age 60, having never fully recovered from his injuries.