Barker sailed from an early age, starting out in Optimist and P Class dinghies, before graduating to Lasers and Finns.

Team New Zealand went on to successfully defend the 2000 Cup 5–0, with Coutts relinquishing his normal helming role to Barker in the last race.

After the 2000 cup there were multiple defections to other syndicates, most notably Coutts and Brad Butterworth to Alinghi and as a result Barker became skipper.

The subsequent internal team review left Barker's reputation intact and he was selected as skipper and helmsman for the 2007 challenge.

This gave Emirates Team New Zealand and Barker the opportunity to race the Swiss challenger Alinghi for the 32nd America's Cup.

Many experts believed Emirates Team New Zealand had a good chance of winning but finished the 2007 America's Cup with a 2–5 race defeat.

Early 2015 saw Grant Dalton offer Barker a shore-based position in order to make room for a new helmsman, Peter Burling and a new skipper, Australian sailor Glenn Ashby.

Barker refused to take this position and accepted the offer to become CEO and skipper of a newly formed Japanese syndicate.