The 31-year-old topped the podium at the Laser European Championships in Barcelona after putting together a string of consistent performances across a week of racing.
It all came down to the final bullet, but Thompson scored 130 points in total, putting him 18 points ahead of Italy's Francesco Marrai, with New Zealand's Andrew McKenzie finishing third.
And the Lymington sailor was delighted to add another title to his collection in challenging conditions, coming behind from fifth to take gold on the final day.
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"I feel really, really pleased," he said. "It's been one of those events which has eluded me for a long time, I've come really close and medalled a few times but never actually managed to win it.
"To finally take the European title means there's just one thing left - the Olympics.
"The week has been incredibly tricky, I knew coming into the regatta that Barcelona wasn't going to be an easy venue and it was going to about the long game and not about necessarily winning one race and then messing up the next one.
"It was going to be about putting together a series and coming out on top at the end and it proved to be that way.”
Thompson will now prepare for the Sailing World Cup in Gamagori, Japan, followed by the Enoshima Olympic Week.
Great Britain achieved three more top-ten finishes in Barcelona, with Lorenzo Chiavarini ending the week as the sixth European in the men's competition.
The British women also enjoyed success as Georgina Povall won the final race to come seventh overall, her best senior European performance to date.
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