The daughter of a former fashion model and actress, Ms. Fleming grew up in Beverly Hills, was a beauty pageant finalist at 15 and entered movies directly out of high school. Although she proved a capable actress in thrillers and comedies, her career was propelled foremost by her exquisite looks. Her figure “practically whistles at itself,” a film colony scribe observed early in her career, and her red hair and green eyes shone spectacularly in Technicolor.

She made an impressive debut as a nymphomaniac in Alfred Hitchcock’s “Spellbound” (1945). “I didn’t even know what a nymphomaniac was,” she later told the Los Angeles Times. “My mother and I had to look it up in the dictionary.”

She appeared in the movie’s opening scene, aggressively flirting with a hospital orderly before breaking his skin with a scratch. “I hate men, I loathe them,” she tells a psychiatrist played by Ingrid Bergman. “One of them so much as touches me, I want to sink my teeth into his hand and bite it off. In fact, I did that once.”

The gossip columnist Hedda Hopper lauded Ms. Fleming as a promising starlet. She was subsequently strangled by a maniac in the gothic chiller “The Spiral Staircase” (1946) and played Robert Mitchum’s treacherous secretary in “Out of the Past” (1947), a celebrated film noir.

She later used her seductive wiles on Bob Hope in “The Great Lover” (1949) and Ronald Reagan in “Tropic Zone” (1953), in which she played a South America plantation owner.

She was a female pirate in “The Golden Hawk” (1952), had an extended bathtub scene in “Pony Express” (1953) starring Charlton Heston, was a belly dancing con artist in “Little Egypt” (1951) and played Cleopatra in “Serpent of the Nile” (1953), with Raymond Burr as an unlikely Mark Antony.

Ms. Fleming’s career was mostly guided by how producers felt she looked in
Technicolor — in short, irresistible.

“Suddenly my green eyes were green green,” she later told People magazine. “My red hair was flaming red. My skin was porcelain white. There was suddenly all this attention on how I looked rather than the roles I was playing. I’d been painted into a corner by the studios, who never wanted more from me than my looking good and waltzing through a parade of films like ‘The Redhead and the Cowboy.’ ”

She might also have mentioned “Yankee Pasha,” “Slightly Scarlet” and “Those Redheads From Seattle.”

When given the chance, Ms. Fleming excelled as a sensual villain. Highlights included “Cry Danger” (1951), a revenge story starring Dick Powell; “Inferno” (1953), a desert-set noir with Robert Ryan; and “While the City Sleeps” (1956), in which she played the faithless wife of a newspaper publisher (Vincent Price).

She also played a gambler opposite Kirk Douglas and Burt Lancaster in the popular western drama “Gunfight at the O.K. Corral” (1957) but was dismayed when much of her role was scissored out. Her career fell into rapid decline, leaving her with starring parts in low-grade Italian films including “The Revolt of the Slaves” (1960).

“My ego demanded it — over there, I was still a big star,” she told author Karen Burroughs Hannsberry for the book “Femme Noir: Bad Girls of Film.”

Ms. Fleming, who spoke often of her Christian faith, formed a popular gospel quartet in the 1950s with actresses Jane Russell and Connie Haines and British-born singer Beryl Davis. Ms. Fleming also kept one foot squarely in the secular world, helping inaugurate Las Vegas’s Tropicana Hotel in 1957 with an eye-popping, skintight Don Loper-designed gown.

She guest-starred in TV series such as “Kung Fu” and “The Love Boat” and made her Broadway debut in a short-lived 1971 revival of Clare Boothe Luce’s catty comedy “The Women.” In that production, she played a hard-living former chorus girl opposite film stars Myrna Loy, Kim Hunter and Alexis Smith.

After marrying her fifth husband, millionaire theater-chain magnate Ted Mann, in 1978, she settled into charity work and lived in what one entertainment writer described as “baronial splendor on a private estate that was once part of the back lot of 20th Century-Fox.”

Marilyn Louis was born in Los Angeles on Aug. 10, 1923. Her father, an insurance broker, persuaded his wife to leave show business. The marriage did not last.

For most of her childhood, Ms. Fleming aspired to a career as a lyric soprano. She also excelled in athletics, leading the women’s volleyball and basketball teams at Beverly Hills High School. She won bit parts in movies before a bedazzled talent scout for producer David O. Selznick signed her to a contract without a screen test.

Her marriages to interior designer Thomas Lane, Hollywood physician Lew Morrell, actor Lang Jeffries and producer-director Hall Bartlett ended in divorce. She was married to Mann until his death in 2001. Two years later, she wed Darol Carlson, who died in 2017. Survivors include a son from her first marriage, Kent Lane; four stepchildren; two granddaughters; five great-grandchildren; and two great-great-grandchildren.

Ms. Fleming was long involved in social service charities, but the death of her older sister from ovarian cancer in 1990 refocused her on the health needs of women with cancer. She helped fund a resource and care operation at the UCLA Medical Center that provided emotional and spiritual support.

“I don’t sit around talking about the past,” she told the Toronto Star in 1993. “I’m working harder than ever for my causes. God gave me great strength — it’s my Mormon upbringing. But every once in a while I’ll turn on the TV and there I am in ‘Yankee Pasha’ or ‘Slightly Scarlet.’ And I watch for a minute and I laugh along with that redheaded girl.”