Dido's mother, Claire, is a French poet and her father is Irish publisher William Armstrong. Named after the mythical Carthaginian queen, Dido was educated at Thornhill Primary, City of London Girls', and Westminster Schools. When she was the age of five, she stole a recorder from school and mastered it around age 10[citation needed]. At the age of six, she attended the Guildhall School of Music in London, England. She began, but did not complete, a degree course in law at Birkbeck College, London. By the time she reached her teens, Dido had already mastered piano, and violin. As an adult, she learned to play the guitar, showcasing her skills to audiences during her 2004 Life For Rent tour.

Following her track, "Thank You" (which had already been used in the 1998 movie Sliding Doors) being sampled by the rapper, Eminem, in his UK #1 single, "Stan" (Dido appeared in the music video, acting as Stan's long-suffering girlfriend), Dido shot to worldwide fame and critical acclaim with her debut album, No Angel, which was already available in the USA, and charted in the UK top 5 on import sales alone. Her debut single, "Here With Me," had already caused demand for the album, as it was used as the theme music for the television programme Roswell and it was later used in the soundtrack for the movie Love Actually).

No Angel was the top-selling album of 2001 in the United Kingdom, debuting at, and returning to, #1 in the official UK albums chart many times throughout 2001. Her second album, Life For Rent, was released September 30, 2003, and became one of the fastest selling albums in UK music history, debuting at #1, and debuting in the US top 5. Dido has also won 4 Brit awards, winning Best British Female artist and Best British Album for No Angel at the 2002 ceremony, and Best British Female artist and Best British Single for "White Flag" at the 2004 ceremony. She also won Best Album for No Angel and Best Newcomer at the 2002 NRJ Music Awards in France. Dido's hairstyle at this time was widely copied and became known as the "Dido flip".

Dido's brother, Rollo Armstrong, is part of the music group Faithless, and gave Dido her big break, by allowing her to provide guest vocals on certain Faithless album tracks, such as "Flowerstand Man" and "Hem Of His Garment." She continued the trend, even after she found fame in her own right, providing vocals for "One Step Too Far," which was released in the UK as a limited edition single, where it debuted at #6, and "No Roots" the title track of the final Faithless album. Rollo also co-writes and produces tracks with Dido, including many tracks on both No Angel and Life For Rent. Dido has also provided guest vocals to tracks by other artists including "Feels Like Fire" for Carlos Santana's 2003 album, Shaman and a duet with Rufus Wainwright entitled "I Eat Dinner (When The Hunger's Gone)" for the "Bridget Jones: The Edge Of Reason" movie soundtrack.

Following her sold-out world tour of 2004, Dido took time out of her worldwide travels to perform at three of the Live 8 concerts on 2 July 2005 - performing in London, then at the Eden Project in Cornwall, before flying over to Paris, performing both solo and a duet with Youssou N'Dour.

In late 2005, Dido began working on her third solo album, writing and recording in the United States. Working in Los Angeles, California with producer Jon Brion, Dido has stated on her website that the new album should be ready early in 2007.

"Poised for world domination, Dido's multi-dimensional pop features the ghostly vocals of the former Faithless chanteuse, supported by an arsenal of millennial studio tricks. Trip-Hop beats and eerie synths pulsate with the futuristic glow of some as-yet-uninvented narcotic on certain songs, while other tunes explore a post-Carly Simon hard AAA style with breathtaking hooks and a surprising show of vocal force. This is truly exciting radio pop that's intent on pushing the mainstream envelope, yet really knows the ropes as far as structuring a hit and planting a good hook in a song." from Rolling Stone

"In its own vapid, curiously sexless way, Life For Rent is actually fascinating stuff, so set against the usual rules of successful music that it starts to look oddly revolutionary" Q Magazine [Oct 2003, p.99]

"Its best moments suggest that Armstrong is unfairly maligned.... At worst, it's twee and bland, aural wallpaper that only someone who didn't really like music could care about. Either way, it isn't going to change anyone's mind about Dido.