She had three older siblings, one of whom, Elisabeth, is an authority on pre-Columbian music and an award-winning composer-violinist who appeared in the film Song of Mexico (1945).

[4] Waldo attended the University of Washington, where her performance in a student theatrical garnered her an award and brought her to the attention of Bing Crosby.

A Paramount Pictures talent scout, who was with Crosby at the time, signed Waldo for a screen test, which led to a contract with the studio.

[citation needed] Waldo appeared in several films in uncredited bit parts and small roles, although she was the leading lady in three Westerns, two of them starring Tim Holt.

She played several characters including Joanne Allen and Mrs. Hodges on the radio show Adventures in Odyssey, produced by Focus on the Family broadcasting.

[citation needed] She co-starred with Jimmy Lydon in the CBS situation comedy Young Love (1949–50), and she had recurring roles on The Adventures of Ozzie and Harriet (as teenager Emmy Lou), The Red Skelton Show, and People Are Funny.

[citation needed] In 1948, the Meet Corliss Archer comic book, using Waldo's likeness, published by Fox Feature Syndicate, appeared for a run of three issues from March to July 1948, using the original scripts.

Waldo also reprised the role of Emmy Lou for some early TV episodes of The Adventures of Ozzie and Harriet.

Waldo was the voice of Princess and Susan in the English-language version of Kagaku ninja tai Gatchaman, known as Battle of the Planets, and Hogatha in The Smurfs.

He quipped, "The punch line, of course, is that fifteen years after the fact, Janet Waldo is still working while for most people, saying the name Tiffany automatically brings to mind a lamp.