[2][1] Born and raised in a family of musicians in Lahaina, Hawaii, Willie began performing at the age of 8 alongside his father, Hawaiian jazz guitarist Manu Kahaialiʻi.

[5] Their recordings won seven Na Hoku Hanohano Awards, part of Willie's total of 19 Hokus as a musician and producer.

[8] In 2007, Willie K became one of very few artists to win a Hoku as part of three different acts – his collaboration with Eric Gilliom called "Barefoot Natives" won Best Contemporary Hawaiian Album, in addition to wins already achieved with Amy and as a solo artist.

[10][11] In February 2018, Willie K was diagnosed with lung cancer and promptly canceled upcoming performances in Honolulu.

[6] In January 2020, in a video posted to Facebook, Willie announced that his cancer was at the terminal stage.