Simpson has released five studio albums in her career: Sweet Kisses (1999), Irresistible (2001), In This Skin (2003), A Public Affair (2006) and Do You Know (2008), which sports her new country sound.

In addition, she has also released two EPs: This is the Remix (2002) and Rejoyce: The Christmas Album (2004).

On October 26, 2002 Simpson married 98 Degrees bandmember Nick Lachey. From 2003 to 2005, Simpson and Lachey let MTV cameras into their home to film their own reality TV show, entitled Newlyweds: Nick and Jessica. She starred in two other shows with Lachey, ABC's Nick and Jessica's Variety Hour and Nick and Jessica: The Christmas Special , in 2004. In 2005, Simpson starred in her first major film role as Daisy Duke in The Dukes of Hazzard.

In 2004, Simpson released a wedding how-to hardcover, entitled I Do: Achieving Your Dream Wedding. She has also released her own line of beauty products, entitled Dessert, and a women's clothing line.

In November 2005, Simpson and Lachey announced their split and on December 16, 2005, Simpson filed for divorce. The divorce was finalized on June 30, 2006.

Simpson's latest album, A Public Affair was released on August 29, 2006. Her next film role is in the comedy Employee of the Month, co-starring Dane Cook, which was released at the end of 2006.