Moore was born Beatrice Melba Hill on October 29, 1945, in New York City, New York, to Gertrude Melba Smith (known professionally as Bonnie Davis) and Teddy Hill, and raised in Harlem, New York, until she was 9 and her divorced mother remarried jazz Pianist Clement Leroy Moorman. She attended Newark Arts High School in Newark, New Jersey, Graduating in 1958.

Moore began her recording career in 1967, cutting the track "Magic Touch" which was left unreleased until 1986. It has become an enormous track on the Northern Soul Scene, eventually leading to Moore performing it live in 2009 at the Baltic Soul Weekender 3 in Germany north of Hamburg. She began her performing career in 1967 as Dionne in the original cast of the musical Hair along with Ronnie Dyson and Diane Keaton.

Following the success of Purlie, Moore landed two big-screen film roles, released two successful albums, 1970's I Got Love and Look What You're Doing to the Man, and co-starred with actor Clifton Davis in the then-couple's own successful variety television series in 1972. Both Moore and Davis revealed that the show was canceled after its brief run when their relationship ended. When Moore's managers and accountants left her in 1973, she returned to Newark and began singing in benefit concerts. Her career picked up after she met record manager and Business promoter Charles Huggins after a performance at the Apollo Theater in 1974. They married in 1975.

In addition to her Tony Award, her music career brought additional accolades. She was nominated for a Grammy Award in 1971 for 'Best New Artist'. Her 1975 second album, Peach Melba, saw her get a Grammy nomination. In 1976, she earned another Grammy nomination for Best Rhythm & Blues Vocal Performance - Female for the song "Lean on Me",.

In 1975 Moore married Charles Huggins and the two formed Hush Productions. After 15 years of marriage, in 1991, Huggins abruptly divorced Moore leaving the singer in financial ruins. In 1999, Huggins filed suit against Moore claiming that she had defamed him in the public as she stated that he abused her economically.

In 1976 she scored her third Grammy nomination with the R&B ballad "Lean on Me", which had been recorded originally by Vivian Reed and later by Moore's idol Aretha Franklin who recorded the song as a B-side to her 1971 hit "Spanish Harlem". The song is most notable for Moore's extended long note at the end. In 1983 she re-recorded the song as a tribute to McCoy, who had died four years earlier. Throughout the rest of the 1970s, Moore struggled to match the success of "This Is It" with minor R&B/dance hits. However, her hit 'Pick me up I'll dance' released in May 1979 produced by McFadden & Whitehead and released on Epic Records did have considerable UK disco success, reaching UK chart position 48, along with a further hit that same year, also produced by McFadden & Whitehead with a cover version of the Bee Gees' hit "You Stepped Into My Life", which reached the top 20 on the R&B charts and 47 on the Billboard Hot 100.

In 1981 Moore signed with Capitol Records and reached the top 5 on the R&B charts with the dance-pop/funk single "Love's Comin' At Ya", which also hit the top 20 in the UK (on EMI America EA 146) and became a sizable hit in some European countries for its post-disco sound and followed by "Mind Up Tonight", which was another top 40 hit in the UK reaching position number 22. A string of R&B hits followed, including 1983's "Keepin' My Lover Satisfied" and "Love Me Right", 1984's "Livin' For Your Love", 1985's "Read My Lips"—which later won Moore a fourth Grammy nomination for Best Female Rock Vocal Performance, making her just the third black Artist after Donna Summer and Michael Jackson to be nominated in the rock category—and 1985's "When You Love Me Like This".

In 1986, she scored two number 1 R&B hits, including the duet "A Little Bit More" with Freddie Jackson and "Falling". She scored other popular R&B hits including "Love the One I'm With (A Lot of Love)" and "It's Been So Long". In 1986, Moore also headlined the CBS television sitcom Melba; its debut aired the same night as the Challenger explosion and the show was abruptly cancelled, though five episodes aired that summer. Her success began to wane as the decade closed, although she managed two further Top 10 R&B hits, "Do You Really (Want My Love)" and "Lift Every Voice and Sing". Moore had a starring role in the 1990 horror film Def by Temptation.

Moore returned to Broadway in 1995 landing a part in Les Misérables. A year later, she started her long-running one-woman show, Sweet Songs of the Soul, later renamed I'm Still Standing. In 2003, Moore was featured in the film, The Fighting Temptations, which starred Cuba Gooding, Jr. and Beyoncé Knowles. In 2007, she landed a role in the Broadway revival of Ain't Misbehavin'. In 2009 independent label Breaking Records released the EP Book of Dreams, in which Moore was featured. That same year Moore told her life story on TV-One's Unsung and later that year released her first R&B album in nearly 20 years, a duet with Phil Perry called The Gift of Love. Her song called "Love Is" debuted on the R&B charts in 2011 at #87.

Moore received the prestigious 2015 Sandy Hosey Lifetime Achievement Award during the Artists Music Guild's 2015 AMG Heritage Awards broadcast held on November 14, 2015, in North Carolina.