WASHINGTON -- When he ran for president in 2012, Mitt Romney had hoped voters would see him as a chief executive who could boost the sluggish American economy. The private equity firm he had founded, Bain Capital , had done well investing in companies like Staples and the Sports Authority . As he liked to remind everyone, he helped save the Winter Olympics in Salt Lake City. Like every presidential candidate, he tried to project confidence and competence.

But privately within his own campaign, Romney could be brutally tough on himself. In this weeks episode of "Candidate Confessional ," his top strategist Stuart Stevens reveals that the former Massachusetts governor and CEO worth hundreds of millions of dollars never seemed satisfied with his own performance, even after his widely praised first presidential debate. Hes very self-critical, Stevens said.

One particular problem area for Romney was his inability to talk about his personal wealth. It was a touchy subject. His refusal to release all of his tax returns became a persistent issue on the trail. Americans ended up knowing more about the car elevator he was building than his charitable work.

Mitt was never very comfortable talking about wealth, Stevens said. He grew up in a family where very, very much the greatest good was not wealth and is really not their value structure. And, you know, hes given vast fortunes to charity.

It was frustrating, Stevens added. Because in many respects, the campaign around Romney saw his biography as an asset. If you look in the Boston area you cant find one thing that has Mitt Romneys name on it," Stevens said. There are a lot of things that they did in charities that they never were comfortable talking about.

Four years later, Donald Trump is taking a different approach. The Republican front-runner is not only comfortable talking about his wealth, he has made it the signature rallying purpose of his campaign. His narcissistic style has drawn ridicule from all corners, including from many of his rivals. But his prime polling position in the days before the Iowa caucus and New Hampshire primary show that flashy self-assuredness can be a draw.

Romney was the opposite. His unease became its own storyline with the Washington Post and others picking it up at the time. The Post pointed out that buried in the infamous 47 percent video theres a fat-cat donor asking Romney why he doesnt stand up for himself. To me, you should be so proud of your wealth, they said. Thats what we all aspire to be. . . . Why not stick up for yourself and say, Why is it bad to be, to aspire to be wealthy and successful?

Stevens remembers one debate prep where they tried to encourage Romney to embrace how he was personally successful. Romney thought this was not a good argument a presidential candidate should make.

"Am I really saying this because I made money, I should be a better president? Im a better person?" Stevens remembered Romney arguing at the time. Talking about his fat bank account, Romney said, would just make him sound arrogant.

Romney just wouldnt go there. "Its part of his religion and his sort of moral structure that you dont brag about these things," Stevens said. "You do good to do good."

Listen to the podcast above, or download it on iTunes . And while you're there, please subscribe to, rate and review our show. Make sure to tune in to next week's episode, when our guest will be Wendy Davis, the Democratic candidate for governor of Texas in 2014.