Born in New Jersey, Gaynor was a singer with the Soul Satisfiers, a jazz/pop band, in the 1960s. Her first solo single was "She'll Be Sorry/Let Me Go Baby" (1965).
"I Will Survive"'s lyrics, written from the point of view of a woman recently dumped telling her ex-lover that she can cope without him and doesn't want anything more to do with him, have become something of an anthem of female emancipation, and the song is still a staple of office parties and karaoke nights, not to mention an anthem in North American gay culture. She also sang on lesser-known disco songs like "Honey Bee" (1973), "Casanova Brown" (1975), and "I Am What I Am" (1983).
She continued recording for many years, releasing "Last Night" in 2000, "Just Keep Thinking About You" in 2001, and "I Never Knew" in 2002.