Jane Powell, an actress and singer who first appeared in movies as a teenager and became a sunny stalwart of Hollywood musicals in the 1940s and 1950s, most notably opposite Fred Astaire in “Royal Wedding” and Howard Keel in “Seven Brides for Seven Brothers,” died Sept. 16 at her home in Wilton, Conn. She was 92.

Her friend Susan Granger confirmed the death but did not give a cause.

A soprano with a 2½ -octave range, Ms. Powell was pressed into show business at age 2 by parents convinced that she was their ticket to fortune during the Depression. She became a radio headliner and star of the war-bonds entertainment circuit in her native Oregon. At 14, her performance of an aria from Bizet’s opera “Carmen” helped her win a Hollywood talent show and a contract with Metro-Goldwyn-Mayer, then a hive of song-and-dance talent, including Astaire, Mickey Rooney, Judy Garland and Gene Kelly.

Producer Joe Pasternak, who had made the young operatic singer Deanna Durbin a movie sensation in the mid-1930s, once proclaimed Ms. Powell his latest find, noting of her 5-foot-1 physique — “big volume without the big poitrine.”

Over the next several years, the blue-eyed, blond and petite Ms. Powell was the coloratura ingenue of frothy romances and Technicolor musicals. She played winsome and wholesome characters — “my real work was being the ‘girl next door,’ ” she once said — and showed off her incandescent charm belting out “Ave Maria” in “Holiday in Mexico” (1946) and “It’s a Most Unusual Day” in “A Date With Judy” (1948).

In “Royal Wedding” (1951), Ms. Powell had the opportunity to abandon moony teenage roles for a more sophisticated part after June Allyson and then Garland dropped out. The movie was about a sister-and-brother Broadway song-and-dance team that goes to London amid preparations for the wedding of Princess Elizabeth to Prince Philip Mountbatten.

The film was based in part on Astaire’s years onstage with his real-life sister, Adele, who left their act to marry an English nobleman. With the choreography already in place, Ms. Powell had just three weeks to learn her dances.

In her 1988 memoir, “The Girl Next Door … And How She Grew,” Ms. Powell recalled Astaire as aloof. It didn’t help their relationship, she wrote, when she casually asked when he and his sister stopped dancing together.

“About 1929, I think,” he said.

“Oh, that’s the year I was born!” she said excitedly.

“They just keep getting younger every year,” she remembered him muttering before walking away.

One of the film’s highlights was the vaudeville-style knockabout number “How Could You Believe Me When I Said I Loved You When You Know I’ve Been a Liar All My Life?,” which featured Astaire as a zoot-suited cad and Ms. Powell, wearing a black wig and a tight sweater, as his coarse, gum-chewing dame. (She also sang the Oscar-nominated ballad “Too Late Now” to a screen amour played by Peter Lawford. )

Three years later, Ms. Powell had the biggest commercial hit of her career with “Seven Brides for Seven Brothers” (1954), a musical about the American frontier that was directed by Stanley Donen and featured dances staged by Michael Kidd.

Ms. Powell played the educated bride of one of the brothers (Keel). Despite acquitting herself well on numbers such as “Wonderful, Wonderful Day,” her performance was largely overshadowed by a richly acrobatic barn dance sequence.

Her career faded with a series of bland musicals opposite the crooning heartthrob Vic Damone. Sensing that MGM was tiring of her services, she severed ties with the studio in 1955 — at age 26 — in the hope of finding greater success on her own.

She failed to recharge her movie career but maintained a vigorous schedule of theater, nightclub and concert appearances over the next 30 years, “traveling,” she once said, “with three dogs and three children” in tow.

In 1974, she replaced Debbie Reynolds in the Broadway run of the nostalgic musical comedy “Irene” — yet another role that showcased her lively charms and masked the loneliness behind her radiant smile.

Ms. Powell was born Suzanne Lorraine Burce in Portland, Ore., on April 1, 1929. Her father quit his job as a Wonder Bread salesman when a promoter and dance teacher lured the family to Oakland, Calif., with the promise of making her the next Shirley Temple, the curly haired moppet star of the Depression.

“My parents thought Oakland was Hollywood,” Ms. Powell wrote in her memoir. “After all, it was in California.” When the promoter vanished with their money, Ms. Powell and her parents returned to Portland, where her father took a job managing the apartment building where they lived.

Ms. Powell continued to attract attention with her vocal talent, eventually winning the favor of MGM mogul Louis B. Mayer. Without so much as a screen test, she was signed to a seven-year contract just as she finished eighth grade. She later said she would have preferred to continue on with friends to high school but signed out of loyalty to her parents who “had sacrificed so much.”

During the filming of her first movie, “Song of the Open Road” (1944), MGM executives decided to rename the young actress after her character, Jane Powell. She followed that performance with “Delightfully Dangerous” (1945). In both cases, critics found her presence unaffected and natural; she later said that was because she had no idea what she was doing.

Buoyed by positive reviews, Ms. Powell was placed in a series of bigger-budget, ever glossier musicals, including “Three Daring Daughters” (1948) with Jeanette MacDonald and “Two Weeks With Love” (1950) with Ricardo Montalban.

Even with a hectic filming schedule, Ms. Powell was constantly on the road. She spent a year playing the crush of the popular radio dummy Charlie McCarthy (voiced by ventriloquist Edgar Bergen) and sang at the inauguration of President Harry S. Truman. At 17, she made the cover of Life magazine.

Through her adolescence on the MGM lot, Ms. Powell made friendships with young stars including Elizabeth Taylor. “I was a bridesmaid at her first wedding, and she was one at mine. I’m glad we stopped it, or it would have become a full-time career,” Ms. Powell joked of her five marriages and Taylor’s eight.

Ms. Powell’s first marriage, to onetime professional ice skater Geary Steffen Jr., ended in divorce after her romance with Gene Nelson, her co-star in the 1953 musical “Three Sailors and a Girl.” Subsequent marriages to Patrick Nerney, James Fitzgerald and David Parlour also ended in divorce.

Her fifth husband was public-relations executive and former child actor Dickie Moore, who interviewed her for his 1984 book, “Twinkle, Twinkle, Little Star: But Don’t Have Sex or Take the Car.” They were married from 1988 to his death in 2015.

Survivors include two children from her first marriage, Geary A. “G.A.” Steffen III and Suzanne Steffen; a daughter from her second marriage, Lindsay Cavalli; and two granddaughters.

Behind what looked like a charmed career, Ms. Powell endured what she described as a turbulent private life, including a long estrangement from her alcoholic mother, her son’s struggle with drugs, and her visceral fear of being alone. To cope, she devoted herself to work, struggling through two years when she lost her singing voice.

Among her many roles, she had a recurring part in the mid-1980s as a strong-willed matriarch on the soap opera “Loving,” and a few years later, she played Alan Thicke’s widowed mother on the sitcom “Growing Pains.” She was a victimized Alzheimer’s patient in a 2002 episode of “Law & Order: Special Victims Unit” and the next year portrayed Mama Mizner in the Stephen Sondheim musical “Road Show” (then called “Bounce”) that ran at the Kennedy Center in Washington but failed to reach Broadway.

Ms. Powell retired soon afterward and said — happily — that she never sang or danced again. She said she disliked appearing at movie retrospectives, which she found an exploitative form of nostalgia, and rarely watched her old films, a reminder of a not entirely happy youth.

“I was very shy. And very lonely,” she told the Geelong Advertiser, an Australian newspaper, in 2005. “I really never felt I belonged. I couldn’t believe it was all happening to me. And I still think that.”

She recalled one time, in the busy blur of her childhood, when a man with slicked-back hair and a rakish mustache approached her in the MGM commissary. “Hiya, Janey girl,” he said, winking.

“It was Clark Gable,” she said. “And I couldn’t think of his name.”