Ferguson was a member of the children's television series Kids Incorporated and the girl group Wild Orchid. In 2001, she left the group and in the subsequent year began to team up with The Black Eyed Peas. With The Black Eyed Peas, she enjoyed a series of hits and albums before she released her solo debut album in September 2006 to success. The Black Eyed Peas enjoyed further success with the release of their third album with Ferguson, The E.N.D. (2009); they attained their first string of Billboard Hot 100 number one songs. She began touring in 2009/2010 with her group and she launched her debut fragrance, Outspoken, under Avon in May 2010 and has since released three more fragrances.
She continued success with The Black Eyed Peas and they released the album The Beginning (2010), which featured three singles, including two number one songs. As Ferguson's five solo singles and six singles with The Black Eyed Peas have reached two million downloads in the United States, Ferguson was the artist with the most two-million sellers by the beginning of 2011.
Ferguson studied dance and began to do voiceover work; she provided the voice for Sally in two made-for-television Peanuts cartoons, It's Flashbeagle, Charlie Brown (1984) and Snoopy's Getting Married, Charlie Brown (1985), as well as on four episodes of The Charlie Brown and Snoopy Show. From 1984 to 1989, she starred on the TV show Kids Incorporated and was the longest running cast member; she starred in the first six seasons of nine total.
The Black Eyed Peas were recording their third album, Elephunk (2003), when will.i.am invited Ferguson to try out for a song called "Shut Up". She got the gig and instantly bonded with the trio, going on to record five additional songs on the album. The following spring, shortly before Elephunk came out, Interscope chairman Jimmy Iovine offered Ferguson a permanent spot to take over vocal duties and fill the void left by background singer Kim Hill's departure in 2000.
From Elephunk came "Where is the Love?", which became The Black Eyed Peas' first major hit: it peaked at number eight on the Billboard Hot 100 and topped the charts in several other countries. The album subsequently spawned "Shut Up", which topped the charts in many markets. The third single from the album, "Hey Mama", reached the top 10 in several European countries and later peaked at number twenty-three in the United States. In 2004, The Black Eyed Peas embarked on the worldwide Elephunk Tour. Their next album, Monkey Business, was released in June 2005. Monkey Business debuted at number two on the Billboard 200. The album's first single, "Don't Phunk with My Heart", reached number three in the United States and earned them a Grammy for Best Rap Performance by a Duo or Group. "Don't Lie", the second single from the album, saw success on the Billboard Hot 100 and reached number fourteen. "My Humps", another song from the album, immediately achieved commercial success in the United States and reached number three on the Hot 100 and number one in Australia. In autumn 2005, The Black Eyed Peas toured with Gwen Stefani, as supporting act. In December 2005, they embarked on the "European Tour". In March 2006, The Black Eyed Peas toured again, as the featured headliner for the Honda Civic Tour.
Ferguson's debut solo album, The Dutchess, was released in September 2006. The Dutchess spawned six hits for Ferguson, which began with "London Bridge", then "Fergalicious", "Glamorous", "Big Girls Don't Cry", "Clumsy" and "Finally". Ferguson scored her fifth consecutive Top 5 hit from The Dutchess after "Clumsy" reached a peak position of number five on the Billboard Hot 100. On November 18, 2007, Ferguson won the Pop or Rock "Favorite Female Artist" at the American Music Awards. In addition, "Big Girls Don't Cry" also earned Ferguson a Grammy nomination for "Best Female Pop Vocal Performance". In December 2007, Blender picked Ferguson as their woman of the year. In 2007, The Black Eyed Peas embarked on the Black Blue & You World Tour and visited more than 20 countries. Ferguson returned to acting in 2006, appearing as a lounge singer in the Poseidon remake. She later had supporting roles in 2007's Grindhouse and the 2009 musical film Nine. Ferguson and other members of the cast of Nine received a Screen Actors Guild Award for Outstanding Performance by a Cast in a Motion Picture nomination for their performance in that film. On December 31, 2006, Ferguson began hosting Dick Clark's New Year's Rockin' Eve on ABC for the pre-taped Hollywood segments after the New Year Ball came down in Times Square.
In December 2012, Ferguson confirmed that she had begun writing her second solo studio album. In April 2013, Ferguson received the "Always Next, Forever Now" award from LOGO TV in honor of her work in the LGBT community. Ferguson has filed a claim at the Los Angeles County Superior Court to legally change her name to Fergie Duhamel and take the last name of her husband Josh Duhamel. Her lawyer claims that she is doing so to "conform to the first name which she is commonly and professionally known as, and has been for many years."
On January 6, 2014, it was re-confirmed that Ferguson was beginning the process of her second studio album. She stated in an interview with radio host Ryan Seacrest that will.i.am will be handling the production; the album is expected to be released solely by Interscope Records in late 2014. In September 2014, it was announced that Ferguson's second studio album has been slated for a 2015 release. Mike Will Made It has been expected to be involved with Ferguson's second album. A new single from Ferguson, titled "L.A. Love (La La)", was released to contemporary hit radio on September 30, 2014.