Jackie Cain, who teamed with her husband, Roy Kral, to form probably the most famous vocal duo in jazz history, melding popular tunes and sophisticated harmonies for more than half a century, died on Monday at her home in Montclair, N.J. She was 86.
Her death was reported by the music writer James Gavin, a friend, who said she had been in declining health since suffering a stroke four years ago.
Performing and recording as Jackie and Roy, Ms. Cain and Mr. Kral, who was also a gifted pianist, created polished interpretations of Broadway standards, jazz tunes and even Beatles songs. They sang in a sophisticated bebop style, enunciating the lyrics crisply and playfully and often forgoing lyrics altogether for energetic scat singing.
Mr. Kral died in 2002.
“Such is their affinity that when they sing harmonies, her airy high tones cushioned by his supple, swinging lows, their notes could be holding hands,” Jon Sall wrote in The Chicago Sun-Times in 1997.
Their voices had similar ranges but were separated by an octave, which made for unusual harmonies. Their easy banter, and Ms. Cain’s striking good looks and sunny personality, added to the appeal of their music, which was routinely praised by jazz critics.
Ms. Cain’s admirers included fellow singers like Billie Holiday, who once said of her to Metronome magazine, “She’s my girl.”
Jacqueline Ruth Cain was born in Milwaukee on May 22, 1928. Her father sold office furniture and managed a community theater. Her parents divorced when she was a child, after which her mother took a job with a photo-imaging company and moved with her to a rooming house.
They could not afford a phonograph, but Jackie loved to listen to music on the radio. She also loved to sing: She was in the chorus in elementary school and an a cappella choir in high school, and she sang with a band organized by a local music store and on a children’s radio show.
“If people wanted someone remembered on their birthday, they’d send cards in or call the station with requests: ‘Please have Little Miss Cain sing this or that,’ ” she said in a 2009 interview with the writer Marc Myers on his blog JazzWax.
Ms. Cain’s first full-time job in music was with Jay Burkhart’s band, which she joined when she was 17. In 1947, a band member, Bob Anderson, took her to a jazz club in Chicago, where Mr. Kral was the pianist with the quartet that was performing.
Mr. Anderson approached Mr. Kral at the bar and suggested that he let Ms. Cain sit in. He said no. In the JazzWax interview, Ms. Cain recalled that Mr. Kral explained why: “Because they never know what they want to sing, and when they tell you their key, it’s usually in the key of Z.”
But she and Mr. Kral talked some more, and it turned out that she knew a song he also knew, “Happiness Is a Thing Called Joe.” He let her sing it, she said, and “the club went nuts.”
In an interview with The Sun-Times in 1997, Mr. Kral suggested that other factors besides music had influenced his decision. “She was a voluptuous blonde, right out of high school,” he said. “She was very convincing.”
Ms. Cain and Mr. Kral began to work as a duo in Chicago clubs. Their breakthrough came when the saxophonist Charlie Ventura hired them for his band. They worked for him for a year and a half and briefly again in 1953. In 1954, they hit the cabaret circuit on their own.
Their relationship was strictly professional, Ms. Cain told The San Francisco Chronicle in 1995, until one day “I leaned over and kissed him. A big, juicy wet one.”
They married in 1949. They had two daughters, Dana Kral, who survives her, and Niki Kral, who died in a car accident in 1973. Ms. Cain is also survived by two stepdaughters, Carol May and Tiffany Bolling-Casares.
The two went on to record nearly 40 albums for Columbia, Verve and other labels. They also sang jingles on television for Halo shampoo, Cheerios and Plymouth. Their repertoire contained more than 400 songs; among their staples were “Mountain Greenery,” “Spring Can Really Hang You Up the Most,” “You Inspire Me” and “It’s a Lovely Day Today.”
After Mr. Kral died, Ms. Cain occasionally performed as a solo singer. Her last performance was in 2007 at a concert celebrating the centennial of the birth of the composer Alec Wilder, a good friend.
In the mid-1950s, Jackie and Roy recorded a harrowingly poetic lament with music by Mr. Wilder and words by Ben Ross Berenberg, “The Winter of My Discontent.” Ms. Cain later remarked that the song (“Like a dream you came, and like a dream you went”) was beyond her life experience at that time.
After hearing her sing it in a nightclub, she recalled, Mr. Wilder asked her never to perform it in a club again. “That’s a song for your last day on earth,” he said.