Hoagy Carmichael, 82, actor, singer and self-taught composer of songs America has been happily humming for 50 years, died Sunday in Rancho Mirage, Calif.

Through such irrepressibly popular compositions as "Stardust," "Georgia on My Mind," "Old Buttermilk Sky," "Lazybones," "Rockin' Chair" and "In the Cool, Cool, Cool of the Evening," Mr. Carmichael made an impregnable claim on the American heart and memory. His entertainment career began in the 1920s and included acting roles in films and on television.

He died after being rushed by ambulance to the emergency room of Eisenhower Memorial Medical Center. Authorities there attributed his death to heart problems.

As an entertainer, on the screen, records or radio or in person, Mr. Carmichael projected an image of easygoing nonchalance underscoring the downhome folksiness that gave many of his songs their particular attraction.

As he appeared in the movies, garters on his sleeves, lank hair falling over his forehead, grinning and singing in his unarguably gravel voice, he was the epitome of the easy-going, ragtime piano player.

Mr. Carmichael was a man with a broodingly intense side that coexisted with his casualness.

"I really should have written two or three times as many songs by my age," he said on reaching 70, "but songwriting can sometimes be murder."

He also was an Indiana University law school graduate who practiced for several years in several places before finally deciding to abandon the bar for the piano bench.

Hoagland Howard Carmichael was born Nov. 22, 1899, in Bloomington, Ind.,the home of his alma mater. He recalled that his childhood home contained few luxuries, but did boast a golden-oak upright piano, which his mother played to the delight of the family.

His mother played ragtime piano at fraternity and sorority dances at the university.

"She took me with her to those parties when I was little," he recalled," and I slept on two chairs, placed side by side."

Although skilled herself, Mr. Carmichael's mother never pressed her son to begin formal study, and he never did.

His piano career began one rainy afternoon, when confined to the house and prevented from playing baseball, he heard the chimes of the college carillon and idly began to pick out the notes with one finger.

"To my amazement," he said later, "I found I was picking them out accurately.

"That day, an incompetent 60-pound third baseman died. The piano had me."

With a few hints and a little guidance from his mother, Mr. Carmichael gained the knack of playing by ear.

Many of his teen-aged years seemed aimless. His family moved. He dropped out of high school, ran a cement mixer in Indianapolis, worked in a slaughterhouse. After constantly being rejected as underweight by the Army during World War I, he was finally accepted. The next day the war ended. Mr. Carmichael recalled drilling only one day.

Eventually he went back to Bloomington to finish high school, and ultimately to enter law school. He played in a band and began to talk to and learn from other musicians, as the jazz age began taking shape.

The man who has been described as the greatest single influence on Mr. Carmichael's career, and for whom one of his sons was named, was jazz great Bix Beiderbecke. Mr. Carmichael first heard Beiderbecke when he played at a fraternity dance at Indiana.

"Bix showed me that jazz could be musical and beautiful as well as hot," Mr. Carmichael said. The spell was so strong that Mr. Carmichael bought a cornet, the instrument his hero played. Mr. Carmichael blew his lips raw. His friends saved him by hiding the horn.

In 1922, he entered law school, fascinated by music, but certain that he needed a proper profession to support himself. While in school he composed two songs, one of them called "Washboard Blues."

After school he went to West Palm Beach, Fla. It was the time of the Florida real estate boom.

"I figured there ought to be work for a good lawyer there because of all that selling and reselling going on," he once told an interviewer. "There probably was, too, but I wasn't a good lawyer . . . a note to me was something that belonged on a musical staff."

Meanwhile, his old song, "Washboard Blues" had been recorded, and in a store, near his Florida law office, he heard it played by Red Nichols and His Five Pennies.

"That did the trick," Mr. Carmichael said later. He was again on his way north, toward the music world. Still ahead, however, were false starts, returns to law and to business, and a failed trip to Hollywood.

Everything was changed by "Stardust." According to a variety of accounts, he had conceived the melody one day in Bloomington and written it later in Florida on the flyleaf of a law book. A 1928 recording did not do well, but later ones, played slower, did better. In 1931 "Stardust" was a hit and Mr. Carmichael was on his way.

Other well-known Carmichael songs include "Two Sleepy People," "Heart and Soul" and "The Nearness of You." In 1951 "In the Cool, Cool, Cool of the Evening" from the film "Here Comes the Groom" won the Academy Award for best song.

His role as Cricket, the saloon piano player in the 1944 film "To Have and Have Not" led to roles in other films including "Young Man With a Horn" and "The Best Years of Our Lives."

His marriage to Ruth Meinardi ended in divorce. Survivors include his second wife, Wanda, and two sons from his first marriage, Randy and Hoagy Bix.