She was one of the seven original cast members of the "Not Ready for Prime Time Players" on the NBC sketch comedy series Saturday Night Live from its inception in 1975 until her departure in 1980.

[4] She grew up in Detroit and spent the winters in Miami Beach, Florida[5] along with the family's nanny, Elizabeth Clementine Gillies, whom she called "Dibby" (and upon whom she based her famous character Emily Litella),[6] and an older brother, Michael.

[17] According to her friend David Saltman in his book Gilda: An Intimate Portrait, she would report on the weather in humorous ways, such as imitating a radio static.

[19] In her senior year at the University of Michigan, Radner dropped out[20] to follow her boyfriend, Canadian sculptor Jeffrey Rubinoff, to Toronto.

Fellow cast members included John Belushi, Chevy Chase,[23] Richard Belzer, Bill Murray, Brian Doyle-Murray, and Rhonda Coullet.

[17] Radner gained wide recognition in 1975 as one of the original "Not Ready for Prime Time Players," the freshman cast of the first season of Saturday Night Live.

[24][25][26] Radner co-wrote much of the material that she performed and collaborated with Alan Zweibel (of the show's writing staff) on the development of sketches that featured her recurring characters.

[27] Between 1975 and 1980, she created many characters, such as the obnoxious personal advice expert Roseanne Roseannadanna (modeled after a New York reporter, Rose Ann Scamardella) and "Baba Wawa", a parody of Barbara Walters.

Another of Radner's invented characters was Emily Litella, an elderly, hard of hearing editorialist who made irate, misinformed comments in interview sketches on SNL’s recurring Weekend Update segment.

In her autobiography, Radner mentioned Murray only once, and in passing: "All the guys [in the National Lampoon group of writers and performers] liked to have me around because I would laugh at them till I peed in my pants and tears rolled out of my eyes.

[34] Radner also gave the commencement address, in character as Roseanne Roseannadanna, to the 1979 graduating class at the Columbia School of Journalism.

[37] The show featured material that was racier than NBC censors would allow on Saturday Night Live, such as the song "Let's Talk Dirty to the Animals."

The three films were not particularly successful, though The Woman In Red performed adequately at the box office, and had the Academy Award winning song "I Just Called To Say I Love You" by Stevie Wonder.

[42] In her autobiography, Radner described Hanky Panky as "not-too-successful,"[43] The Woman in Red as "a nice enough success,"[44] and Haunted Honeymoon as "a bomb....a box-office disaster.

Radner had romantic involvements with several Saturday Night Live castmates, including Bill Murray (after a previous romance with his brother Brian Doyle-Murray) and Dan Aykroyd.

In 1985, while on the set of Haunted Honeymoon in the United Kingdom, Radner began experiencing severe fatigue, and pain in her upper legs.

She sought medical treatment, and for a period of 10 months, various doctors, most of them in Los Angeles, gave her several diagnoses that all turned out to be wrong; meanwhile, she continued to experience pain.

[20] During those 10 months, she also faced hardships such as the publication of Hill and Weingrad's highly publicized book about Saturday Night Live, which provided many details about her eating disorder[36][20] as well as the financial failure of Haunted Honeymoon, which had grossed only $8,000,000 in the United States, entering the box-office-returns ranking at number 8, then slipping to 14 the following week.

Radner wrote in It's Always Something: They found an old photo of me looking frightened from a 'Saturday Night Live' sketch and blew that up to make the point.

Life did a March 1988 cover story on her illness, titled "Gilda Radner's Answer to Cancer: Healing the Body with Mind and Heart."

Wanting to return to television, Radner guest-starred on It's Garry Shandling's Show on March 18, 1988, unannounced, mentioning on-camera that a cancer diagnosis and treatment explained the long hiatus in her entertainment career.

[58][59] After the appearance, the HBO president Michael Fuchs discussed the possibility of giving Radner a new show created by Zweibel and Shandling.

[66] In Rolling Stone's February 2015 appraisal of all 141 SNL cast members to date, Radner was ranked ninth in importance.

"In the years between Mary Tyler Moore and Seinfeld's Elaine, Radner was the prototype for the brainy city girl with a bundle of neuroses.

"[67] Radner has been cited as an influence by many writers and comedians such as Lena Dunham, Melissa McCarthy, Amy Poehler, and Maya Rudolph.

'"[68] Radner's death helped raise awareness of the early detection of ovarian cancer and the connection to familial epidemiology.

[71] Wilder established the Gilda Radner Hereditary Cancer Program at Cedars-Sinai to screen high-risk candidates (such as women of Ashkenazi Jewish descent) and to run basic diagnostic tests.

He testified before a Congressional committee that Radner's condition had been misdiagnosed and that if doctors had inquired more deeply into her family background they would have learned that her grandmother, aunt, and a cousin had all died of ovarian cancer, and therefore they might have attacked the disease earlier.

Hosted by Saturday Night Live alumnus Molly Shannon, the special featured highlights from her career and appearances by friends and co-stars Victor Garber, Kermit the Frog, Eugene Levy, Steve Martin, Paul Shaffer, Lily Tomlin, and Barbara Walters.

[78] In 2015, for the Saturday Night Live 40th Anniversary Special, Radner was honored with other deceased cast and crew members over the show's history.