The film is based on a true story.
"I always saw it as this love story between this guy and his wife who is gone, and really I don't think I could have played the role 10 years ago," said Damon. "I think having kids and being married really made this... I just related to the whole story."
Damon and Crowe hope that moviegoers will shed a few tears of joy.
"Cameron described it to me as, he said, 'I want this movie to be like a piece of joy. I want to put this piece of joy out into the world.' He said, 'I think we can use it right now.' And so that was kind of what we all felt we were assembled to do," Damon said.
Scarlett Johansson plays the park's head zookeeper and she teaches Damon's character a thing or two along the way.
In the film, he has two kids. In real life, Damon and his wife have four daughters. He expects them all to go to college, even though he's 12 credits short of his own degree.
"I got a job, you know? That's why I left school, and I will explain to them that I am on an extended leave of absence. I did not drop out. That door is not... I still have my foot in the door," said Damon.
Meantime, he continues his education in the art of making movies.
"We Bought a Zoo" is rated PG.