The Filipino-American group Kai started in 1992. AC Lorenzo invited Andrew Gapuz and Leo Chan to perform at a San Francisco benefit concert. Following, they began working as a trio and in 1995, added Errol Viray and Lorenzo's cousin Andrey Silva.

At first, the group went by the name APEX but changed their name to Kai, standing for "kaibigan", a Tagalog word meaning friendship. They were signed to HB Records, a local studio, and began working on an album. Their debut single, 'Say You'll Stay' was released shortly after and received strong radio play. This helped them get signed by Geffen in 1997. In 1998, they released their self-titled debut album, becoming the second Filipino American recording artist to release an album on a major record label (Jocelyn Enriquez beat the group to it in 1997).

Their only charting single was the previously mentioned 'Say You'll Stay' which reached #59 on the Hot 100.

The group saw a lineup change in 2000 as Andrew Gapuz left the group and Johnny Misa took his place. Together, the group then released a sophomore album, The Promise, with singles "Every Little Thing" and "It Might Be You."

In addition to their albums, the group released several songs on Asian compilations within America. These tracks included "Last To Know" on Serenade Volume 1 and a cover of Shai's "Come With Me" on AsianAvenue.com Plugged In Volume 3 in 2001.

In 2001, the group broke up and members Andrey Silva and Errol Viray tried to keep the group's name as a duo. However, they later changed the name to 6th Day as they merged with Jose "Sway" Penala of American Idol and Cyrus Mallare of the group Innerlude.

6th Day released an album in 2005 titled Forever Starts Today.