Kevin Richardson was born and raised in Lexington, Kentucky, and is of Italian-Irish descent. Back in his younger years, he was a chess club member and acted in school plays such as "Bye, Bye Birdie" at Estill County High School in Kentucky. He was also a football quarterback. He used to play the role of "Aladdin" and one of the Teenage Mutant Ninja Turtles at Disney World, where he also met his wife Kristin Richardson who was playing "Belle" in "Beauty and the Beast". He worked at Disney World until he joined the Backstreet Boysin 1993. Later that year, Brian Littrell who is Richardson's maternal first cousin, joined the group. After the joining of Littrell, the quintet offically took shape. Richardson was part of the popular boy band until 2006, when he announced his departure. He recorded a total of six albums with the group.

In 2002, he played the role of "Billy Flynn" in the Broadway production of Chicago. He also performed this role in London's West End as well as Toronto in November 2006 – December 2006.

In June 2006, Richardson left the Backstreet Boysto pursue other interests and "move on with the next chapter of [his] life." He issued the following statement on the band's website on June 23, 2006: "After 13 years of what can only be described as a dream come true, I have decided that it is time to leave the Backstreet Boys It was a very tough decision for me but one that was necessary in order to move on with the next chapter of my life. Howard, Brian, Alex and Nick will always be my little brothers and have my utmost love and support. I would like to thank the Backstreet fans for all the beautiful memories we have shared together and look forward to including you in the next phase of my life. I wish my brothers continued success and look forward to their new album."

On November 14, 2006, he came back to New York City with many Chicago Alumni for the 10th Anniversary for Chicago. After that from late November 2006 - December 3, 2006 he went to Toronto to play Billy Flynn. From February 4, 2007 - March 4, 2007 he went to do Chicago in Japan, for the first time.

Richardson is composing the soundtrack of a forthcoming animated movie, The Spirit Bear, which is due out in 2008.

In February 2000, Richardson and Willits' engagement was announced on MTV, and were married four months later on June 17, 2000. The couple's first child, a son Mason, was born on July 3, 2007.

He has been a model for Versace with Ashton Kutcher He was ranked third for 4 consecutive years for the top model of the year.