The Hackney-born jumper saw off tough competition from RomaniaÃ¢â‚¬â„¢s Marian Oprea and France’s Teddy Tamgho.
Oprea eventually claimed silver but Idowu produced some of the best jumps of his career to add to his already impressive repertoire.
“I’ve always worked hard and by the grace of god I’ve come out a gold medallist,” Idowu told BBC Sport.
“I’ve worked hard for this. People think I’m a lucky athlete, but I’m not lucky, I’ve been doing this for 10 years now. I win gold medals. That’s what I do.
“Hopefully now people will stop doubting me.”
Despite the success he has achieved in Barcelona, Idowu remains focused on achieving Olympic success in 2012.
“There is one more medal in my career I need to win and that will come in a couple of years,” he said.
Success in London would complete a career set of European, World, Commonwealth and Olympic titles.