While touring with a stock company producing "The Ship", Young was discovered by a Metro-Goldwyn-Mayer talent scout who signed the fledgling actor to a contract.

In 1936, MGM summarily loaned Young to Gaumont British in the U.K. for two films; the first, Secret Agent, was directed by Alfred Hitchcock, while the other, It's Love Again, co-starred Jessie Matthews.

After his contract with MGM expired, Young starred in light comedies and dramas for studios such as 20th Century Fox, United Artists, and RKO Radio Pictures.

He played the second lead in Secret of the Incas (1954) starring Charlton Heston, the film upon which Raiders of the Lost Ark was subsequently loosely based.

Young's career had begun an incremental and almost imperceptible decline, despite a propitious beginning as a freelance actor without the nurturing of a major studio.

Today, Young is most remembered as the affable insurance salesman in the long-running popular sitcom Father Knows Best (1949–1954 on radio, 1954–1960 on television), for which he and his co-star Jane Wyatt won several Emmy Awards.

[2] Elinor Donahue ("Betty"), Billy Gray ("Bud"), and Lauren Chapin ("Kathy") played the Anderson children in the television version.

Young then created, produced, and starred with Ford Rainey and Constance Moore in the nostalgic CBS comedy series Window on Main Street (1961–1962).

[3] The popular phrase "I'm not a doctor, but I play one on TV" from a commercial for Vicks 44 cough medicine has been erroneously attributed to Young due to his Marcus Welby, MD fame.

Despite his trademark portrayal of happy, well-adjusted characters, Young's bitterness toward Hollywood casting practices never diminished, and he suffered from depression and alcoholism, culminating in a suicide attempt in January 1991.