[5] At the age of seven, she moved with her parents, two sisters, and brother to Los Angeles, where she began voice, piano and dance lessons.

After graduating from Susan Miller Dorsey High School, she enrolled in UCLA, where she earned a degree in business administration.

She met Billy Davis Jr. in 1966 when he established the 5th Dimension, then called the Versatiles, which also included Ron Townson and Florence LaRue.

By the early 1970s, McCoo began to sing lead on the group's remaining hits, "One Less Bell to Answer", "(Last Night) I Didn't Get to Sleep at All", and "If I Could Reach You".

[9] They became the first African American married couple to host a network television series, The Marilyn McCoo & Billy Davis Jr. Show, on CBS in summer 1977.

This would be the duo's last album until thirty years later; in October 2008 the pair released The Many Faces of Love, a collection of hit songs from the 1960s and 1970s.

After breaking from the 5th Dimension to perform as a duo and subsequently releasing three albums, McCoo and Davis Jr. next decided to go solo professionally in the early 1980s.

McCoo began hosting the popular American music television show Solid Gold from 1981 to 1984 and returned from 1986 to 1988.

She also embarked on a nightclub and concert act and went on to play the role of Tamara Price on the soap opera Days of Our Lives in 1986, as a friend of the character Marlena Evans.

McCoo won her eighth Grammy (which also included work with the 5th Dimension) for her contributions to Quincy Jones' Handel's Messiah.

McCoo is married to fellow 5th Dimension bandmate Billy Davis Jr. On July 26, 2019, they celebrated their 50th wedding anniversary.