She was born Ann Lennox on Christmas Day, 1954, in Aberdeen, Scotland. Lennox was an only child and the family lived in a small two-roomed apartment in a block of flats with communal laundry facilities. Her father and his family were musical and enjoyed singing. Lennox had piano lessons at school from the age of seven years at the cost of £4.00 per term, which was a lot for the family to afford.

Later on, Lennox won a place at the Royal Academy of Music in London, where she studied the flute and classical music for three years. She lived on a student grant and worked part-time jobs for extra money. In 2006, the academy made her an honorary Fellow. Lennox also was made a Fellow of the Royal Scottish Academy of Music and Drama that year.

Between 1977 and 1980, Lennox was the lead singer of The Tourists, a moderately successful British pop band and her first collaboration with Dave Stewart. During the time they were in The Tourists, Stewart and Lennox were involved in a relationship, though this had ended by the time they formed Eurythmics.

Lennox and Stewart's second collaboration, the 1980s synthpop duo Eurythmics, resulted in her most notable fame, as the duo's alto, soul-tinged lead singer. Early in Eurythmics's career, Lennox was known for her androgyny, wearing suits and once impersonating Elvis Presley Eurythmics released a long line of singles in the 1980s, including "Sweet Dreams (Are Made of This)", "Here Comes the Rain Again", "Who's That Girl?", "Would I Lie to You?", "There Must Be an Angel (Playing with My Heart)", "Missionary Man", "You Have Placed a Chill in My Heart", and "Don't Ask Me Why", among others. Though Eurythmics never officially disbanded, Lennox made a fairly clear break from Stewart in 1990. Thereafter, she began a long and equally-successful solo career.

From the beginning of her career, Lennox has experimented with her image both as an artist and as a woman. She matured as a public figure in the late 20th century. She has managed her image astutely, both as a means of interpreting and marketing her music. Because of her immense success, Annie Lennox has also amassed a substantial fortune, estimated at £30 million over the years with Eurythmics and as a solo artist.

Though it was produced by Dave Stewart, a 1988 single from the movie Scrooged with Al Green, "Put a Little Love in Your Heart" was credited to Lennox and Green, and therefore can be considered her first release outside a band identity. This one-off "solo" single climbed all the way to #2 on the US Adult Contemporary chart.

Her 1992 solo début album, Diva, was a commercial and critical success, charting #1 in UK, #6 in Germany, and #23 in the US. Lennox's profile was boosted by Diva's singles, which included "Why" and "Walking on Broken Glass". "Little Bird" also formed a double A-side with "Love Song for a Vampire", a soundtrack cut for Francis Ford Coppola's 1992 movie Bram Stoker's Dracula.

Although Lennox's profile decreased for a period due to her desire to bring up her two children outside of the media's glare, she continued to record albums. Her second release, Medusa, was an album of cover songs, including songs originally performed by Bob Marleyand The Clash. It was released in 1995, three years after Diva. The single "No More I Love You's" received the 1995 Grammy Award for Best Female Pop Vocal Performance. In 1997, Lennox re-recorded Eurythmics' track "Angel" for the Diana, Princess of Wales tribute album.

In 2003, Lennox released her third solo album, Bare. Lennox also embarked on a worldwide solo tour to promote the album. In 2004, Lennox won the Academy Award for Best Song for "Into the West" from the film The Lord of the Rings: The Return of the King at the 76th Academy Awards, which she co-wrote with lyricist Fran Walsh and composer Howard Shore. The song also won a Grammy award and a Golden Globe award. She had previously recorded "Use Well the Days" for the movie, which incorporates a number of quotations from Tolkien in its lyrics. This song was not used in the film, but it appears on a bonus DVD included with the "special edition" of the movie's soundtrack CD.

Lennox's fourth solo album, Songs of Mass Destruction, was greatly anticipated by her fans between 2006 and 2007. Lennox described it as "a dark album, but the world is a dark place. It's fraught, it's turbulent. Most people's lives are underscored with dramas of all kinds: there's ups, there's downs - the flickering candle." She added, "Half the people are drinking or drugging themselves to numb it. A lot of people are in pain."