She was born Tina Blacker, an only child, to a Jewish family in New York City, and attended Miami University. She started her career as a model and nightclub singer while she studied at the Actors Studio.

In 1957, she and Julie Newmar made their Broadway debuts in Li'l Abner. Her album It's Time for Tina was also released that year, with songs such as "Embraceable You" and "I'm in the Mood for Love".

She made her Hollywood film debut in 1958 in God's Little Acre. She became an in-demand leading lady for major stars like Robert Taylor and Robert Ryan often playing somber roles quite unlike the glamourous pinup photographs she had become famous for in the late 1950's. Further roles followed, on Broadway and in films in Italy and Hollywood, but they failed to accelerate her career.

In 1964 she was cast as "movie star" Ginger Grant on the television series Gilligan's Island. Louise finally achieved a level of fame and recognition; however, she was unhappy with the role and worried that it would typecast her. The role did make her a pop icon of the era and in 2005 an episode of TV Land Top Ten ranked her #2 as television's all-time sex symbol, second only to Heather Locklear.

After the series ended in 1967, she continued to work in films and made numerous guest appearances in various television series. She appeared as a doomed suburban housewife in the original The Stepford Wives (1975), and both the film and her performance were well received.

Despite this success, she languished in secondary roles and in later years blamed her lack of credibility as an actress on the typecasting that had followed her success with Gilligan's Island, a program she had grown to detest. She has declined to participate in any of the reunion television movies and specials, but did appear on a TV Land award show with the other surviving cast members. In the 1990s she was reunited with costars Bob Denver, Dawn Wells, and Russell Johnson in cameo appearances on an episode of Roseanne. Her relations with series' star Denver were rumored to be strained but in 2005 she wrote a brief affectionate memorial of him in the year finale issue of Entertainment Weekly.

Louise appeared as a semi-regular character in the prime-time soap opera Dallas and made an appearance on Married... with Children. In 2005, Louise joined the cast of the soap opera Passions in the role of Helen Winthrop. Her new autobiography is scheduled for release in mid-2006, to accompanied by a North American book tour.