Ms. Smith, shown with Frank Sinatra, received a Grammy nomination for “Keely Sings Sinatra” in 2001. (Concord Records via AP)

Keely Smith, a smoky-voiced balladeer who became a nightclub sensation in the 1950s with her then-husband, the comically disruptive entertainer Louis Prima, and who gradually emerged from his shadow as an acclaimed solo performer, died Dec. 16 at a nursing home in Palm Springs, Calf. She was 89.

The cause was aortic stenosis, said her publicist, Bob Merlis.

Prima and Ms. Smith’s act offered a seamless blend of anarchy and sophistication, with his sassy beast to her cool beauty. Their physical and musical chemistry brought them a mass following, hit records and $25,000 a week on the Las Vegas Strip, helping make Sin City, then a second-tier desert outpost, a major show-business destination.

They won the first Grammy Award for best performance by a vocal group for their 1958 version of "That Old Black Magic" and foreshadowed the popularity of Sonny and Cher, the ­husband-and-wife variety-show team who played up insouciant banter and mismatched physicality in the 1960s and '70s.

Ms. Smith’s musicianship was peerless — with a clean and caressing phrasing style — and she exuded sex appeal with her tight blouses and satin and taffeta gowns. No one’s idea of a matinee idol, the burly Prima was almost 20 years Ms. Smith’s senior. The New Orleans-born trumpeter, singer and irrepressible stage performer was a combination of Louis Armstrong and Jerry Lewis.

Ms. Smith in 2008. (Kevork Djansezian/AP)

He belched, gestured suggestively and rewrote lyrics to emphasize their bawdy possibilities. As Ms. Smith sang a plaintive rendition of "I Got It Bad and That Ain't Good," Prima interjected in a raspy bellow, "I've got it good, and it ain't bad!"

Ms. Smith, sporting her signature page-boy haircut, brought an imperturbably blithe spirit to the festivities, hewing to the melody despite Prima's efforts to throw her off.

“The less she did, the funnier it was,” music critic Will Friedwald wrote in the New York Sun in 2005. “Their act was a brilliant juxtaposition of maximalism and a minimalism: Prima would be practically climbing the walls and swinging from the light fixtures. She just stood there with a stone-faced expression.”

Prima was the impresario, crafting Ms. Smith's stage persona as sultry and playful. In a nod to the emerging interest in rock-and-roll, Prima hired a rhythmically propulsive backup band, the Witnesses , that included the hard-driving New Orleans tenor saxophonist Sam Butera .

They rehearsed religiously but let spontaneity reign when the spotlight came on.

“We never knew what tunes Louis was going to call,” Ms. Smith told Friedwald. “He would start with ‘When You’re Smiling’ and end with ‘When the Saints Go Marching In,’ but it was anyone’s guess what he would call in between. And you know the band never used a page of music? They had all those charts memorized.”

They recorded albums for Capitol Records, re-creating jazz and pop standards in an array of styles and tempos: swing jazz, “shuffling” upbeat jump blues, Italian tarantellas and Dixieland.

Some of their best-known titles included "Just a Gigolo/I Ain't Got Nobody" (done as a medley), "That Old Black Magic" and "I've Got You Under My Skin." They also performed in movies and on television, giving with each piece the impression of an endless party.

The clowning belied marital and professional discord. Music reviewers began to notice Ms. Smith’s beguiling way with the Great American Songbook, asserting that she was the real musical draw of the two.

The attention aroused jealousies in Prima that worsened as Ms. Smith’s solo projects increasingly became commercial and critical hits.

She earned a Grammy nomination for her million-selling 1958 single "I Wish You Love," featuring a high-energy Nelson Riddle arrangement. She also recorded duets with Frank Sinatra. "Everyone thought we were having a big romance," she later told the San Francisco Chronicle. "We didn't, but I could kick myself now."

Ms. Smith also co-starred as a singer in "Thunder Road" (1958), a crime drama about moonshiners, opposite Robert Mitchum. Three years later, she and Prima performed at John F. Kennedy's presidential inauguration before enduring an acrimonious personal and professional split.

Sinatra signed her to his Reprise label, leading to albums that included "Little Girl Blue/Little Girl New" (1963), with Riddle conducting and arranging. "The result was a tour de force of an album that presented Smith as the solo star she deserved to be," music scholar Matt Collar wrote in a review for the website AllMusic.

Starting in 1965, she took a hiatus from performing to raise her two daughters from her marriage to Prima and then slowly reemerged as a headliner on cruise ships and at hotel lounges.

She saw her profile buoyed in the 1980s and '90s when rock stars plumbed some of the old Prima material. David Lee Roth remade their recording of "Just a Gigolo/I Ain't Got Nobody," and Brian Setzer had a hit with "Jump, Jive an' Wail"; the original was also revived in a popular television ad for Gap khakis.

Ms. Smith told The Record of Bergen County, N.J., that she had been invited to sing backup to Setzer but declined, declaring that she “wasn’t going to sing backup on his album, or anybody else’s.”

“When Louis and I broke up, he told me that I’d be nothing without him. And I believed him,” she said. “I realized I’m having fun doing what I’m doing now. It’s my stage. There’s no Louis up there.”

Dorothy Jacqueline Keely was born in Norfolk on March 9, 1928. She grew up with her mother and stepfather, a carpenter whose surname, Smith, she later adopted as her stage name. They lived on the edge of poverty, she said, in a part of town that gave rise to “every thief, every hooker, every anybody that did anything bad that landed up in jail.”

A self-taught singer, she debuted at age 11 on a local children’s radio show and soon was performing at military bases and Norfolk nightclubs for $5 a week — enough money to pay for her school clothes.

On a family vacation to Atlantic City in 1947, she saw Prima’s band for the first time at the Steel Pier ballroom and found herself “absolutely mesmerized” by his rowdy performing style.

The following summer, in 1948, the bandleader was performing at a Norfolk waterfront club when he announced from the stage that the group needed a new female singer. Word reached Ms. Smith, who was on the beach. She raced in, borrowing a skirt and blouse to wear over her bathing suit. She won the audition barefoot. The next year, she cut her first record with Prima, "Five Foot Two (Eyes of Blue)."

Prima wed Ms. Smith in 1953, a month after divorcing his third wife. In the late 1960s, Ms. Smith married and divorced rockabilly singer and record producer Jimmy Bowen . She later spent 30 years in Palm Springs as a domestic partner of Charles J. Caci, who had ties to organized crime and sang under the name Bobby Milano . Prima died in 1978.

Survivors include her two daughters, Toni Prima of Palm Springs and Luanne Prima of Los Angeles and Palm Springs; and two brothers.

As part of her late-career flowering, Ms. Smith cut several albums for the Concord Jazz label, including the Grammy-nominated "Keely Sings Sinatra" in 2001, that led to many performing dates at marquee Manhattan clubs.

Having received one of the first Grammys ever awarded, Ms. Smith was invited to participate in the golden anniversary of the music industry honors, in 2008, and was incongruously paired with rapper Kid Rock for a duet of "That Old Black Magic."

The reviews were not kind — to him, anyway — but Ms. Smith tried to make the best of it. “He is so cute and so sexy, you can’t believe it,” she said. “I had never seen him before.”