"I was so frustrated to see the way the establishment of our party blew the last few elections, whether it is the faith-based funding election, whether it was 100,000 job cuts," Brown said, when speaking on CBC Radio's Metro Morning on Tuesday.
"I thought the party was run by a top-down group that didn't listen to the membership, that didn't value the membership."
Brown said the party has to change this dynamic in order to become more competitive at the polls.
"You want to win? You listen to your teammates, you value and respect the membership and I want to take that value set, those attitudes to rebuilding the PC party," he said.
Brown is also critical of some Tories' reluctance to embrace ideas from outside of the conservative ranks.
'No monopoly on a good idea'
"This gang that ran the party, they came out and voted against the last budget without even seeing it. And my philosophy is this: there's no monopoly on a good idea. If an idea comes from the NDP, from the Liberals, from a red Tory, from a social conservative, if it makes sense for Ontario, I'll vote for it," he said.
"What I'm not going to bind myself to, is to say that I'm only going to vote for something that comes from one persuasion."
Describing himself as a "pragmatic conservative," Brown said that "anything that benefits Ontario, anything that helps families, that helps create jobs, that helps enhance the quality of life in Ontario, I will rally behind, regardless of where that idea originates."
The last time the Tories won a general election in Ontario was in 1999. Since 2003, the Liberals have held either a minority or majority government.
Brown, a three-term MP from Barrie, is vying for the leadership against Christine Elliott, the deputy leader of the party who has wide support from the caucus.
They are the last two candidates standing in the months-long leadership contest that was triggered by the departure of Tim Hudak, who stepped down after the Tories were defeated in last year's election.
PC party members began voting for their preferred candidate on Sunday. A second day of voting will follow on Thursday. The result will be announced this weekend.
If he wins, Brown said he'll immediately be reaching out to Elliott, in a bid to bring her into the fold.
"I think she has a lot to offer and she's someone that I would value in the Conservative movement going forward," he said.
Elliott is due to appear on Metro Morning on Wednesday.