Simpson was born in Abilene, Texas and raised in Richardson, a suburb of Dallas. She is the daughter of Joe (a Baptist youth minister) and Tina Simpson and has a younger sister, Ashlee, who launched her own music career in mid-2004. Jessica started singing at the age of twelve as a part of her Baptist church choir. At the same age, she made an unsuccessful application for The New Mickey Mouse Club, which starred fellow singers Christina Aguilera, Britney Spears and Justin Timberlake, among other future stars.

Jessica attended J.J. Pearce High School in Richardson, Texas. Simpson was discovered singing at a church camp by a head of a small contemporary Christian record label and recorded an album over the next three years, but the label went out of business before the album could be released. She dropped out her senior year in order to tour and promote her demo album, which was funded by her grandmother, Joyce (thus the reason for the name Rejoyce: The Christmas Album); she later earned her GED. During this time, she toured with the Christian Youth Conference circuit performing with Kirk Franklin, God’s Property and CeCe Winans. She and her father sold copies of the album after her performances.

Tommy Mottola of Columbia Records obtained a copy of the album and, thinking she had potential as a pop singer, signed her as such. Jessica eliminated the Christian influences from her appearance and music.

On November 23, 1999, Simpson released her debut pop album Sweet Kisses, reaching a peak of #25 on the U.S. Billboard 200 chart and also making the top 40 of the UK charts. The album proved to be a success, selling 2 million copies in the U.S.. Her first single, the platinum-selling “I Wanna Love You Forever”, reached the top 5 of the U.S. Billboard Hot 100 singles chart and the top 10 in Canada and the UK in late 1999. Her second single, a duet with then-boyfriend, now-husband Nick Lachey of 98 Degrees, “Where You Are”, was a modest radio hit. The last single off the album, the John Mellencamp-sampled “I Think I’m in Love With You”, was a top 40 hit in the U.S. and a top 20 hit in Canada and the UK. In 2000, Simpson won two Teen Choice Awards for Choice Breakout Artist and Love Song of the Year (“Where You Are” featuring Nick Lachey).

Simpson’s sophomore effort Irresistible, released on June 5, 2001, reached the top 10 of the Billboard 200 and top 20 of the Canadian album charts. Despite this improvement, the album’s sales were less than satisfactory; to date, it has only managed to be certified gold in the U.S. for selling over 500,000 copies. The title track, which was featured as the lead single, went top 20 in the U.S., Canada and the UK, as well as top 40 in Australia and Switzerland. A follow-up single entitled “A Little Bit” was also released, but failed to achieve much success apart from going top 20 in Portugal. Compared to her competition in pop princesses and ex-Mouseketeers Aguilera and Spears, Simpson seemed to be lagging behind in terms of chart success and sales.

Between her second and third albums, Simpson released a collection of remixes entitled This Is The Remix on July 2, 2002. However, the collection failed to even chart on the Billboard 200, suffering from lack of promotion.On October 26, 2002, Simpson wed Nick Lachey.

During the Summer of 2003, Simpson and husband Lachey’s reality show Newlyweds began airing on MTV. Though Simpson was moderately famous before the series began, the show is considered responsible for transforming her into a true star.Throughout the run of three seasons, she often appeared as a stereotype of a dumb blonde, notably when she asked whether the Chicken of the Sea tuna she was eating was chicken or fish, and when she thought that buffalo wings were made from actual buffalo. Her apparent stupidity made the show a huge hit, making the average rating for each episode about 1.4 million viewers. When introduced to Interior Secretary Gale Norton, Simpson responded: “You’ve done a nice job decorating the White House”.

Banking on the success of her new popularity, she appeared on a variety show with Lachey on the ABC called the Nick and Jessica Variety Hour on April 11, 2004. A pilot for a sitcom on ABC was also planned, but was rejected by network executives in May 2004. During the Summer of 2004, Simpson won three Teen Choice Awards for Choice Female Fashion Icon, Choice Hottie Female and Choice Female Reality/Variety TV Star, further proving that Newlyweds had greatly strengthened her overall popularity. In 2005, the series won a People’s Choice Award for Favorite Reality Show. A couple of months later, the show finally wrapped.

Coinciding with Newlyweds, her third album, In This Skin, was released on August 19, 2003. On a whole, the record featured a much more mature sound compared to her earlier releases. Though the album initially was not a huge success, it got its chance to rebound on the charts when a special collector’s edition was released on March 2, 2004. This helped Skin to reach a peak of #2 on the Billboard 200 and the top 40 of the UK charts, due largely in part to the success of Newlyweds. The album eventually proved to be her most successful, selling 3 million copies in the U.S. and allowing her teetering music career a second chance. The lead single off the album was a cover of Diane Warren’s “Sweetest Sin”; the song was not very successful, however, and caused a backlash in sales of Skin early on. The follow-up single, the gold-selling “With You”, enjoyed much more success, and became her biggest hit since “I Wanna Love You Forever”. The song went top 10 in the UK and top 20 in the U.S. and Australia, as well as on world adult charts. The third single, a cover of Berlin’s “Take My Breath Away”, also went top 20 in the U.S.. A cover version of Robbie Williams’ “Angels” was released as the fourth and final single.