Havelock first competed in grasstrack racing, winning the British Junior Championship, before following his father into speedway. Havelock showed his potential early in his speedway career, winning the Suffolk Open Championship at Mildenhall as a 16-year-old in 1984, only two weeks after qualifying for a licence. Havelock started his league career with local club Middlesbrough Tigers in 1985, moving from reserve to the main body of the team by May, before moving to the Bradford Dukes in 1987, where he spent the next ten seasons. A season with the Eastbourne Eagles was followed by five seasons with the Poole Pirates until 2003. During this time Havelock also spent the 1986/87 and 1988/89 seasons in Australia based at the North Arm Speedway in Adelaide. In 1987, Havelock won the European Under-21 Championship. This would be the final year that it would be called the European Championship as it became the World Under-21 Championship from 1988. The highlight of his career was when he won the World Championship in 1992 at the Olympic Stadium in Wrocław, Poland. Havelock, the first British World Champion since Michael Lee in 1980, finished three points clear of 1990 World Champion Per Jonsson of Sweden, and four in front of DaneGert Handberg He has also represented Great Britain in the Speedway World Team Cup finals six times, finishing runner-up in 1990 and in the Speedway World Cup four times, finishing runner-up in 2004. Havelock missed most of the 1996 season after seriously injuring his back whilst representing England in a test match against Australia at Poole in the July. Havelock had ridden in the first two of the Speedway Grand Prix meetings that season. His 2012 season was ended early by a crash in March in which he was hit by Derek Sneddon's bike, resulting in a broken collarbone, a broken arm, and broken ribs. As a consequence of the injuries to his arm, Gary Havelock announced his retirement from speedway on 22 February 2013. A week later he was named as the new team manager of Coventry Bees.
Off track
Havelock was banned for the entire 1989 season after he tested positive for cannabis at the British League Riders' Championship meeting in 1988. At the 2007 BSPAAnnual General Meeting, Great Britain team manager Neil Middleditch announced that he would be "happy to continue" in the position but recommended that Havelock should be his successor once he has retired from racing, stating "he would take to it like a duck to water". Middleditch also mentioned he would be happy for Havelock to act as his assistant. Havelock appeared in the Sky TV football show Premier LeagueAll Stars in 2007, representing eventual winners Middlesbrough F.C.. Havelock is a patron of the charity National Association for Bikers with a Disability.
