Despite his father Chris being an England great, Broad made the confession at a recent function at the Long Room at Lord's.
Broad explained the winning culture of the Australians was a joy to watch in his younger years.
"I was very proud of Dad and what he achieved in Ashes cricket, but actually my heroes were slightly different growing up. They weren’t English," Broad said.
"As a young kid you get influenced by winning teams, don’t you? So Glenn McGrath is my hero and watching Australian players succeed, I enjoyed that.
"Unfortunately my heroes are Australian."
Broad will lead the English attack in the fourth Ashes Test at Trentbridge in the absence of usual spearhead James Anderson.
A victory for Broad and co will give England an unassailable 3-1 lead in the series.
"My family will be at the ground. I’ve got a good record at Trent Bridge and have taken a Test hat-trick there. People talk a lot about sports psychology and when you feel good in your environment you’re more likely to perform," Broad wrote in The Daily Mail.
"There will be a bit more pressure on me perhaps in Jimmy’s absence but hopefully that will bring the best out of me.
"You don’t know what’s going to happen but hopefully I’ll take on that extra responsibility to ensure we’re not crying out for Jimmy over the next couple of days."
The fourth Test at Trentbridge begins on Thursday August 6 at 8.00pm (AEST).