Lyndell sang in gospel churches as a child; though she was white, she sang in both white and black churches, and eventually began singing with R&B groups as a teenager.
In the 1960s she sang as a support act with James Brown and Ike & Tina Turner, and in 1967, following a stint as lead female vocalist for The Fabulous Georgia Soul Twisters, Atlanta disc jockey Dave Crawford tipped her to Stax Records producers Isaac Hayes and David Porter. They recorded her first single, "Bring Your Love Back to Me", in December 1967 and released it on Volt Records, but the song did not become a hit. In 1968 she did a second session, cutting the tune "What a Man"; this song reached #50 on the Billboard R&B charts. In response to the success of her single, she received threats from white supremacist groups such as the Ku Klux Klan, and retired from performance soon after. She remained out of music and lived in Gainesville for the next 25 years.
In 1993, rap group Salt-n-Pepa sampled "What a Man" for their hit single "Whatta Man", which was a massive hit. In the wake of the single's success, Lyndell began performing again, and in 2003, at the opening of the Stax Museum, she performed "What a Man" live for the first time ever.
She recorded two singles for Volt records in the late 60's with producer Dave Crawford, neither of which had any major sucees at the time; but "What A Man" became a huge hit in 1994 when remade by Salt 'N' Pepa and En Vogue