Michel Legrand, a French composer with more than 200 screen credits, notably the jazzy movie operas “The Umbrellas of Cherbourg” and “The Young Girls of Rochefort,” and whose tunefully romantic music for “The Thomas Crown Affair,” “Summer of ’42” and “Yentl” brought him Oscars, died Jan. 26 at his home in Paris. He was 86.

The death was announced on his website, but no other details were provided.

As a teenage piano virtuoso in post-World War II Paris, Mr. Legrand irked his classical conservatory teachers when he turned his focus toward jazz. But his penchant for seductive tunes, informed by a classicist’s knowledge of the orchestra, made him one of the best-known and most prolific composers of his generation.

After a run of hitmaking jazz albums, including collaborations with trumpeter Miles Davis and saxophonist John Coltrane, Mr. Legrand drew international attention in 1964 with “The Umbrellas of Cherbourg.”

Director Jacques Demy’s melancholy musical was about an auto mechanic (Nino Castelnuovo) and a shop owner’s daughter (Catherine Deneuve) who fall in love in the French coastal city but are driven apart by war and circumstance.

Every word of dialogue was sung — a rarity at the movies and a generation past the heyday of film musicals. Mr. Legrand concocted a bebop recitative that exalted even the most banal asides (“It rattles a bit when the motor’s cold, but that’s normal”), and he wrote a heartbreaking aria for the star-crossed lovers, whose story Demy captured in rapturously bold visual colors.

The concept took Mr. Legrand more than a year to compose. He told NPR in 1998: “We couldn’t find any producer in Paris who would put one franc in an adventure like that. Nobody believed in it. . . . We knew that our movie, if by any miracle we could make it, would be a flop for sure.”

Demy, who also served as lyricist, found backing from Mag Bodard, one of the few female producers at the time, and recorded the entire soundtrack with professional singers, which the film’s actors then meticulously lip-synced on set.

Even decades later, the film’s emotional impact could cause normally hard-bitten critics to swoon. Much of that potency was owed to Mr. Legrand’s central ballad, “I Will Wait for You,” which gained the composer an Oscar nomination and was later covered by entertainers including Frank Sinatra, Tony Bennett, Liza Minnelli and Itzhak Perlman.

Chicago Tribune movie critic Michael Wilmington wrote in 1996 that Mr. Legrand’s “music is so deceptively light, bubbly and seemingly inconsequential that the movie, at first, seems to be courting musical as well as dramatic banality. Yet when ‘Cherbourg’ segues into its big ballad at the first defloration and railroad-station parting of the lovers — the unforgettable ‘I Will Wait for You’ — there’s such a startling surge of emotion that it almost catches you unawares. ‘I Will Wait for You,’ with its throbbing, melodic hook, its sense of melancholy, is a pop apotheosis: the song everyone heard and remembered.”

Mr. Legrand and Demy followed their success with “The Young Girls of Rochefort” (1967), a pastel-hued musical starring Deneuve, her sister Françoise Dorléac and Gene Kelly. The two filmmakers shared an Oscar nomination for their score.

The next year, Mr. Legrand was lured to Hollywood for the Steve McQueen-Faye Dunaway heist film “The Thomas Crown Affair” (1968) and found an Oscar gold mine with lyricists Alan and Marilyn Bergman. Their song “The Windmills of Your Mind,” with a hypnotic melody spinning like its subject, earned the composer his first Academy Award (his score was also nominated) and later became a Top 40 hit sung by Dusty Springfield.

Mr. Legrand returned to the Academy Awards stage for his score of “Summer of ’42” (1971), the story of a sensitive teenager’s crush on his mature neighbor (Jennifer O’Neill).

While some critics sniffed at Mr. Legrand’s film music as lushly saccharine, middle-of-the-road easy listening, there was no doubt he hit a commercial sweet spot. When singer and actress Barbra Streisand made her directorial debut in 1983 with “Yentl,” she called on Mr. Legrand to supply its songs; he had arranged and conducted her 1966 album “Je m’appelle Barbra,” which reached No. 5 on the Billboard charts.

“Yentl” was an adaptation of Isaac Bashevis Singer’s story about a young Jewish woman who disguises herself as a boy to become a scholar and winds up falling in love with her classmate. Mr. Legrand penned pining, bittersweet numbers — again with the Bergmans — that served as Yentl’s inner monologue.

The standout “Papa, Can You Hear Me?” — which Streisand performs after her character’s father dies at the beginning of the movie and operatically reprises at the end — earned another Oscar nomination and found chart success. Mr. Legrand won his third and final Oscar for the film’s score.

Michel Jean Legrand was born in the Paris suburb of Becon-les-Bruyeres on Feb. 24, 1932. He was 3 when his father, Raymond, a prominent conductor and composer, walked out on the family, leaving him in the care of his mother and an older sister. He found security in an old piano.

“It was one of the few things my father forgot to take when he left,” Mr. Legrand told the Toronto Star in 2009. “I sat down and put my two hands on the piano and began playing, trying to re-create a song I had heard on the radio. It became my only friend, my only love and, very quickly, my mother realized it was all I could do with my life.”

By 9, he was such a ferociously skilled player that the Paris Conservatory made an exception to its minimum age policy of 14 by admitting him. He won a slew of awards at the conservatory but found himself drawn to American jazz, saying that after hearing trumpeter Dizzy Gillespie in a Paris concert, he felt he had “discovered another world, another planet.”

Soon he was orchestrating for cabaret singers Edith Piaf and Yves Montand, and he became musical director for entertainer Maurice Chevalier. In 1954, at 22, he recorded a jazz album, released in the United States as “I Love Paris,” which sold hundreds of thousands of copies.

Because of his commercial pull, he was given carte blanche for one of his next albums, “Legrand Jazz” (1958), which featured reinterpretations of jazz standards by an all-star team that included Davis, Coltrane, Bill Evans, Art Farmer, Milt Hinton and Donald Byrd. Decades later, Los Angeles Times jazz critic Leonard Feather called “Legrand Jazz” “unquestionably one of the most successful orchestral jazz albums of all time.”

In the early 1960s, Mr. Legrand composed for French New Wave movie directors including Demy’s wife, Agnés Varda (“Cleo from 5 to 7”), and Jean-Luc Godard (“A Woman Is a Woman,” “My Life to Live,” “Band of Outsiders”).

In Hollywood, he received Oscar nominations for the songs “What Are You Doing the Rest of Your Life?” from the 1969 film “The Happy Ending”; “Pieces of Dreams” for the 1970 film of the same name; and “How Do You Keep the Music Playing?” from the 1982 film “Best Friends.”

Mr. Legrand’s other credits included “Brian’s Song” (1971), the popular TV movie about a gridiron friendship; “Lady Sings the Blues” (1972) starring Diana Ross as the heroine-doomed singer Billie Holiday; Orson Welles’s acclaimed documentary about con men, “F for Fake” (1973); and the James Bond film “Never Say Never Again” (1983).

He directed and co-wrote the well-received film “Five Days in June” (1989), a semi-autobiographical drama that chronicled the romantic and musical exploits of a young musician named Michel Legrand (Matthieu Rozé) against the backdrop of the Normandy landings in World War II. He also composed the Tony Award-nominated romantic-comedy musical “Amour,” which had a short Broadway run in 2002.

Mr. Legrand’s marriages to fashion model Christine Bouchard and actress-producer Isabelle Rondon ended in divorce. For years, he and harpist Catherine Michel were live-in partners. In 2014, he married actress Macha Méril. He had several children, but a complete list of survivors was not immediately available.

Mr. Legrand won five Grammy Awards and, in 1990, was inducted into the Songwriters Hall of Fame.

“Joy and pain are the inexorable rhythms of life,” Mr. Legrand once told an interviewer about the tensions he said defined the craftsmanship of song. “It’s impossible to play one chord without striking the other. That contradiction is life’s mystique. In music, there is profound exultation of expression. But, for a moment of high-level happiness, there are 10 tons of sweat and sorrow and fatigue and fury.”