The 51-year-old actor appeared at an auction in aid of The Journalism Foundation, which promotes free and independent journalism throughout the world.
He successfully bid USD 22,400 for a three-day golf holiday at Scotland's famous St Andrews links, reported Contactmusic.
Other guests at the event, which raised a total of USD 240,000, included Mick Jagger's ex-wife Jerry Hall and Grant's former lover Jemima Khan.
The actor has been a leading light in a campaign for a reform of the press in his native UK, and in November he made a headline-grabbing appearance at a public hearing into newspaper standards.
He had then told the Leveson Inquiry in London that his privacy had been invaded by tabloids and he had been "chased at speed" by photographers.