I wouldn't necessary call him a hero, but Billy Beane, general manager of the Oakland A's, is certainly a true rationalist. He is the protagonist of the nonfiction book Moneyball by Michael Lewis.
Before Beane, decisions about what baseball players to draft were mostly made by professional scouts. These guys spent their time driving across the country to find young players and watch them play. Serious attention was paid to how a player "looked" - his physique, his grace, and his personality (aggressiveness was a big plus). Statistics were factored into the decision, but not given much weight, since 1) statistics about a player's high school career didn't imply much about his professional career, and 2) people weren't counting the right things. For example, batting average turns out to be much less important than on-base percentage (the latter takes walks into account, the former doesn't).
Billy Beane helped to change that. He was able to turn a team with a relatively small budget (the A's spent about a third of what the Yankees spent on salaries) into a consistent winner. Like Munger, he looked for value: players who, because of inadequacies in other teams' evaluation methods, could be hired cheaply relative to their talents.
Light reading about 'Rationalist Heroes'.
I am not sure how useful people find having personal heroes. I would argue that they are definitely useful for children. Perhaps I haven't really grown up enough yet (growing up without a father possibly contributed), but I like to have some people in my head I label as "I wonder what would X think about this". Many times they've set me straight through their ideas. Other times I've had to reprimand them, though unfortunately they never get the memo.
One living example is Charlie Munger.
He was an early practical adopter of the cognitive biases framework, and moreover he clearly put it into context of "something to protect":
"not understanding human misjudgment was reducing my ability to help everything I loved"
(The quote is from his talk on "Misjudgment" which is worth reading on its own http://vinvesting.com/docs/munger/human_misjudgement.html)
One interesting point is that Charlie is seemingly a Christian. I have a deep suspicion that he believes that religion is valuable, for the time, as a payload delivering mechanism.
“Economic systems work better when there’s an extreme reliability ethos. And the traditional way to get a reliability ethos, at least in past generations in America, was through religion. The religions instilled guilt. … And this guilt, derived from religion, has been a huge driver of a reliability ethos, which has been very helpful to economic outcomes for man.”
Also, judge for yourself from his recommended reading list - looks like something out of an Atheist's Bookshelf.