John Kitakis, founder of Ko'olau, is the father. His sons are: Andrew Kitakis, who started Hawaii Music Supply and The Ukulele Site; & Noa Bonk, Ko'olau Master Luthier and runs the company.
From TUS website written in 2013 by Andrew Kitakis:
"About 20 years ago my dad (John Kitakis) started Ko’olau Guitar & Ukulele Company. That pride of craftsmanship and aim for the finest quality have always been at the heart of Ko’olau and many serious musicians were and still are delighted by this. 12 years ago, as I left to start Hawaii Music Supply, my brother Noa took over the Ko’olau custom shop building and has continued to perfect this art. Dad set forth on a new venture; To make a Ko’olau quality instrument at a more affordable price. This has been no casual effort. It’s taken him many years but he now provides a truly great brand, our best selling line of ukuleles. Even though quality has become consistent, he still travels to the island of Java to work with the luthiers there and continue improving."
From the TUS website written in 2017:
"For many years John Kitakis and Noa Bonk did mostly warranty repair for Martin, Taylor and other guitar companies. Occasionally they built custom guitars and other instruments. Seeing the need for a professional quality ukulele company, John started Ko’olau Ukulele in 1996. The shop was right at foothills of the Ko’olau mountains in Kaneohe. They later relocated to the other side of the mountain, Wahiawa, but for over 20 years now they have been working full time to create the best musical instruments for artists and enthusiasts.
"About 10 years ago John started the Pono line in Indonesia and Noa took over the custom building for Ko’olau. Noa’s had small crews in the past but now focuses on the finest quality possible with just him building and Ryan Condon finishing. Together, what they have been offering for the last few years is impeccable craftsmanship and master level voicing. Ko’olau ukuleles are light in weight, full with rich overtones, gorgeous with the best woods, and truly a joy to play."