Janet Waldo, a voice-over actress who played sprightly teenagers for decades on popular cartoon shows, most notably "The Jetsons," died on Sunday at her home in Encino, Calif. She was 96.
The television historian Stu Shostak, a friend, said the cause was an inoperable brain tumor.
Ms. Waldo broke through as the title character on "Meet Corliss Archer," a CBS radio show about a girl next door that ran from the early 1940s until the mid-1950s.
In 1962 Ms. Waldo landed her first, and most enduring, animation role. She played Judy Jetson, the teenage daughter on "The Jetsons," Hanna-Barbera's futuristic answer to "The Flintstones." The show initially lasted only one season; those episodes ran in syndication until new ones were made beginning in 1985.
Ms. Waldo played Judy in the television movie "Rockin' With Judy Jetson" (1988), but not in "Jetsons: The Movie," a feature film released in 1990. After Ms. Waldo finished recording Judy's part, the studio decided to replace her with the pop singer Tiffany to drum up ticket sales.
"I was totally crushed," she told The Los Angeles Times in 1990. "I originated the character, and I feel very sentimental about Judy."
The film was the last time the original cast recorded together. George O'Hanlon, who voiced George Jetson, died in 1989, shortly after finishing his part.