The British royal drama, starring Colin Firth as stuttering monarch King George VI, was tipped to sweep the Globes, but The Social Network was the surprise winner.
Producer Weinstein admits the snub hit him hard, but reveals it made him more "motivated" to push the campaign to take the Academy Awards' best honour as a result.
He tells Piers Morgan Tonight, "Here's what we did... we never stopped. We didn't admit defeat - we were defeated, but we just kept going. We worked hard, nose to grindstone, tenacity.
"I think losing the Golden Globe for Best Picture was, for me, feeling that was something we could win... Instead of making me quit, it motivated me the complete opposite way and at that point I said however many hours there are in a day, I'm gonna expand the amount.
"There's only one thing you can do, you've got to get people to see your movie. You've got to create an atmosphere where people can appreciate your movie. To us it was the timelessness of the movie. A lot of people said this movie or that movie is more younger, hipper, cooler, socially relevant... you have to say the timelessness, a classic movie, conquers all and that was what we wanted to get across."
And Weinstein was ecstatic to learn his campaigning had paid off as the period film was named Best Picture at the Hollywood prizegiving on Sunday (27Feb11): "I was elated, just absolutely jumping for joy. It was an amazing experience. It was fantastic."
The film also landed three other prizes - Best Actor in a Leading Role (Colin Firth), Best Director (Tom Hooper) and Best Screenplay - Original (David Seidler).