A founding member of Hui 'Ohana, a group he formed in the early '70s with his twin brother, Nedward, and a cousin, Dennis Pavao, Kaapana was instrumental in bringing the slack key to stages around the globe. Launching a solo career in 1983, Kaapana has continued to garner acclaim for his improvisational melodies and falsetto vocals. The Honolulu Advertiser called Kaapana "friendly, generous, self-effacing, a little kolohe (rascally) and a flat-out genius at just about any stringed instrument that can be fingerpicked."

Born on the southeastern shore of the Big Island, in the shadow of the Kilauea volcano, Kaapana grew up without electricity, television, or a telephone. As a youngster, he was inspired by the playing of an uncle, Fred, who had taught himself to play slack key guitar. Kaapana continues to tune his guitar in the unique tunings that, according to legend, were revealed to his uncle in a series of dreams. Kaapana was equally influenced by such slack key guitarists as Gabby Pahinui and Raymond Kane. Kaapana's first success as a soloist came when his 1983 album, Lima Wela, received the prestigious Na Hoku Hanohano award as Best Instrumental Album. Performing in the Smithsonian's Festival of American Folklife in 1988, he toured with the National Council of Traditional Arts program Masters of the Steel String Guitar from 1990 to 1992.

Kaapana has collaborated with a wide range of musicians. A concert with steel string guitarist Bob Brozman was released on a video, Kila Kila Meets Ki Ho'alu, in 1997. The following year he recorded an album, Waltz of the Wind, with guest musicians including Brozman, Sam Bush, Jerry Douglas, Alison Krauss, Sonny Landreth, Ricky Skaggs, and George Winston. Following 2000's Black Sand, he again collaborated with Brozman on In the Saddle. A pair of Grammy-nominated albums, 2005's Kiho'alu: Hawaiian Slack Key Guitar and 2006's Grand Master Slack Key Guitar, brought Kaapana more widespread exposure and acclaim, as did appearances on a couple of high-profile slack key compilations. His output over the coming decade would remain consistent, with solo releases like 2012's The Legend and a couple of albums dedicated solely to the autoharp (2014's Jus' Cruzin') and the ukulele (2016's Jus' Press, Vol. 2). A greatest-hits compilation on Jus Press Productions appeared in 2017. Kaapana was also the recipient of a National Endowment for the Arts National Heritage Fellowship Award. ~ Craig Harris