The dark, petulant beauty of this petite American film and musical star worked to her advantage, especially in her early dramatic career. Anne Marie Blythe was born of Irish stock to Harry and Annie (nee Lynch) Blythe on August 16, 1928 in Mt. Kisco, New York. Her parents split while she was young and she, her mother and elder sister, Dorothy, moved to New York City, where the girls attended various Catholic schools. Already determined at an early age to perform, Ann attended Manhattan's Professional Children's School and was already a seasoned radio performer, particularly on soap dramas, while in elementary school. A member of New York's Children's Opera Company, the young girl made an important Broadway debut in 1941 at age 13 as the daughter of the characters played by Paul Lukas and Mady Christians in the classic Lillian Hellman WWII drama "Watch on the Rhine", billed as Anne (with an extra "e") Blyth. She stayed with the show for two years.

While touring with the play in Los Angeles, the teenager was noticed by director Henry Koster at Universal and given a screen test. Signed on at age 16 as Ann (without the "e") Blyth, the pretty, photographic colleen displayed her warbling talent in her debut film, Chip Off the Old Block (1944), a swing-era teen musical starring Universal song-and-dance favorites Donald O'Connor and Peggy Ryan. She followed it pleasantly enough with other "B" tune-fests such as The Merry Monahans (1944) and Babes on Swing Street (1944). It wasn't until Warner Bros. borrowed her to make self-sacrificing mother Joan Crawford's life pure hell as the malicious, spiteful daughter Veda in the film classic Ömre bedel kadın (1945) that she really clicked with viewers and set up her dramatic career. With murder on her young character's mind, Hollywood stood up and took notice of this fresh-faced talent.

Although Blyth lost the Best Supporting Actress Oscar that year to another Anne (Anne Revere), she was borrowed again by Warner Bros. to film Tehlike İşareti (1945). During filming, she suffered a broken back in a sledding accident while briefly vacationing in Lake Arrowhead and had to be replaced in the role. After a long convalescence (over a year and a half in a back brace) Universal used her in a wheelchair-bound cameo in Vahşi Kuvvet (1947).

Her first starring role was an inauspicious one opposite Sonny Tufts in Swell Guy (1946), but she finally began gaining some momentum again. Instead of offering her musical gifts, she continued her serious streak with Killer McCoy (1947) and a dangerously calculated role in Another Part of the Forest (1948), a prequel to Öldürünceye Kadar (1941) in which Blyth played the Bette Davis role of Regina at a younger age. Her attempts at lighter comedy were mild at best, playing a fetching creature of the sea opposite William Powell in Deniz Kızının Aşkı (1948) and a teen infatuated with a much-older film star, Robert Montgomery, in Once More, My Darling (1949).

At full-throttle as a star in the early 1950s, Blyth transitioned easily among glossy operettas, wide-eyed comedies and all-out melodramas, some of which tended to be overbaked and, thereby, overplayed. When not dishing out the high dramatics of an adopted girl searching for her birth mother in Our Very Own (1950) or a wrongly-convicted murderess in Thunder on the Hill (1951), she was introducing classic standards as wife to Mario Lanza in The Great Caruso (1951) or playing pert and perky in such light confections as Katie Did It (1950). A well-embraced romantic leading lady, she made her last film for Universal playing a Russian countess courted by Gregory Peck in Dünyalar hâkimi (1952). MGM eventually optioned her for its musical outings, having borrowed her a couple of times previously. She became a chief operatic rival to Kathryn Grayson at the studio during that time. Grayson, however, fared much better than Blyth, who was given rather stilted vehicles.

Catching Howard Keel's roving eye while costumed to the nines in the underwhelming Rose Marie (1954) and his daughter in Kismet (1955), she also gussied up other stiff proceedings like Talebe Prens (1954) and Saltanat hırsızları (1955) will attest. Unfortunately, Blyth came to MGM at the tail end of the Golden Age of musicals and probably suffered for it. She was dropped by the studio in 1956. She reunited with old Universal co-star Donald O'Connor in Sönen yıldız (1957). Blyth ended her film career on a high note, however, playing the tragic title role in the Hayat çemberi (1957) opposite a gorgeously smirking Paul Newman. She had a field day as the piano-sitting, kerchief-holding, liquor-swilling torch singer whose train wreck of a personal life was destined for celluloid. Disappointing for her personally, no doubt, was that her singing voice had to be dubbed (albeit superbly) by the highly emotive, non-operatic songstress Gogi Grant.

Through with films, Blyth's main concentration (after her family) were musical theatre and television. Over the years a number of classic songs were tailored to suit her glorious lyric soprano both in concert form and on the civic light opera/summer stock stages. "The Sound of Music", "The King and I", "Carnival", "Bittersweet", "South Pacific", "Show Boat" and "A Little Night Music" are but a few of her stage credits. During this time Blyth appeared as the typical American housewife for Hostess in its Twinkie, cupcake and fruit pie commercials, a job that lasted well over a decade. She made the last of her sporadic TV guest appearances on Quincy M.E. (1976) and Cinayet Dosyası (1984) in the mid-1980s.

Married since 1953 to Dr. James McNulty, the brother of late Irish tenor Dennis Day, she is the mother of five, Blyth continues to be seen occasionally at social functions and conventions.