Brathwaite excelled in the COJHL with the Smiths Falls Bears and in Junior B with the Orillia Terriers. In 1989-90, he won eleven games as an OHL rookie with the Oshawa Generals. That spring, he took over from the injured Kevin Butt to lead the team to a stunning overtime win over the Kitchener Rangers in the Memorial Cup final. Brathwaite also played with the London Knights and Detroit Junior Wings before signing as a free agent with the Edmonton Oilers in October 1993. A few months earlier, he made news by scoring a goal while playing for Detroit.

The talented netminder was a solid back up in Edmonton for three years before being relegated to the minors. During the 1998-99 season, Brathwaite resurrected his NHL hopes by leading Canada to the Spengler Cup title in Switzerland. Shortly after returning to Canada he was signed by the Calgary Flames. Brathwaite sparkled during the last 28 games of the season. In 1999-2000 he registered five shutouts and 25 wins as the Flames' season-long battle to make the playoffs fell short. Brathwaite was excellent again in 2000-01 with a sparkling 2.32 goals against average before the off-season trade to St. Louis.

Brathwaite went on to play almost two full seasons with the Blues before he was subsequently released from the team after St. Louis traded for Chris Osgood at the trading deadline in 2003. Upon his release from the Blues, Brathwaite signed as a free-agent with the Columbus Blue Jackets.

As a member of the Blue Jackets, Brathwaite would struggle in his 21 games with the club and as a result would not be re-signed by the club. Brathwaite would spend the next two seasons with Ak Bars Kazan of the Russian Super League.

In the summer of 2006, the Atlanta Thrashers signed the free agent goaltender.