Her father is the first graduate of statistics in Nigeria. She spent her early years in Nigeria having contacts with her hometown, Ikere-Ekiti where her grandfather was one of the most influential men.
After her parents separated when she was four, her mother, Hayes moved to Essex, England with Sade and her brother Banji. After her secondary school education, she moved to London to study fashion design at Saint Martin's School of Art.
In between her time in school, she took up modelling jobs. Later on, she joined a band, Pride and became a backup singer. An enthusiast, she came into songwriting partnership with the group's guitarist, Stuart Matthewman and they performed at gigs. One song that caught the attention of recording companies was "Smooth Operator."
In 1983, Adu and Matthewman left Pride to start a band, Sade. They were joined by the keyboardist Andrew Hale, bassist Paul Denman and drummer Paul Cook. Adu became so popular so that at her first show in Heaven's nightclub, over 1000 people did not get access to the club. That same year, she performed at the US and by October, Epic Records signed her and in 1984 signed her band.
After the group's signing, Adu dropped an album, "Diamond Life". The album became the best-selling debut by a female vocalist and one of the best-selling albums of all-time with an international sale of over six million copies as well as stayed at number one on music top charts.
The following year, they released "Promise". The album stayed on the Billboard 200, got multiple platinum certifications in the US and Europe and earned the group a Grammy Award for Best New Artist
In 1988, the group released "Stronger Than Pride" and in 1992, "Love Deluxe." She went on hiatus after the birth of her child.
In 1986, she landed a role in a film "Absolute Beginners" and in 2000, released "Lovers Rock". "Lover's Rock" was unlike her jazz style. It took on a pop sound and won the Grammy Award for Best Pop Vocal Album.
In 2002, she was awarded the Officer of the Order of the British Empire(OBE). In 2010, the group released "Soldier of Love" and it got the Grammy Award for Best R&B Performance by a Duo or Group with Vocals.
In 2018, she did the soundtrack "Flower of the Universe" for Disney's 2018 film A Wrinkle in Time.