In 2018, O'Brien won his 8th Oceanic & Australian Title in Formula Windsurfing at the Downunder Pro at Royal Queensland Yacht Squadron in Brisbane.

[7] O'Brien worked for three years as the windsurfing coach for the QLD State High Performance Sailing unit at Royal Queensland Yacht Squadron club in Brisbane.

[9] Later he coached five-time Olympian and two-time PBA World Champion Jessica Crisp to her first ISAF World Cup gold medal in 2009 at the SailMelbourne regatta and a clean sweep of the Australian Sail-Downunder Series by also taking gold in the SailSydney regatta at Woollahra Sailing Club in the RS:X Olympic class.

[13] He is based in Poland with his son, John O'Brien and partner Agata, the grand-daughter of prominent Polish military general Mieczysław Dachowski.

In 2012 O'Brien launched the first ever windsurfing fitness training program GetWindsurfFit[14] in conjunction with his trainer Nic Pillonel from Switzerland.