Facebook founder Mark Zuckerberg gives a rousing commencement address at Harvard University

Facebook CEO Mark Zuckerberg is a deeply private person and can sometimes come off flat as a dial tone. But at Harvard on Thursday he was charming, thoughtful, emotionally raw, and profoundly introspective. Five years after he ruffled feathers on Wall Street by wearing his customary grayT-shirt and jeans during meetings with prospective Facebook IPO investors, Zuckerberg wore a crisp suit and blue tie and opened his remarks with a wry joke at his own expense.

"You all accomplished something I didn't. If I get through this speech today, it will be the first time I actually finish something at Harvard," quipped Zuckerberg, who famously dropped out of Harvard after launching Facebook in his college dorm room 12 years ago.

Zuckerberg spoke at a podium without a teleprompter, and focused on channeling the entrepreneurial spirit exhibited by his generation, to push for big ideas and big projects, equal economic opportunity for all and a global community.

"The greatest successes come from having the freedom to fail," said Zuckerberg, during his rousing commencement speech at Harvard.

He acknowledged that it's a luxury he himself was afforded, but too many are not. That's why billionaires like him should pay for a financial safety net that allows everyone to find their purpose, he said.

"If I had to support my family growing up instead of having time to code, if I didn't know I'd be fine if Facebook didn't work out, I wouldn't be standing here today," said Zuckerberg, whose father was a successful dentist.

Zuckerberg said he experimented often as a student. "An entrepreneurial culture thrives when it's easy to try lots of new ideas. Facebook wasn't the first thing I built," he says. "I also built games, chat systems, study tools and music players."

"I'm not alone," continues Zuckerberg. "J.K. Rowling got rejected 12 times before publishing "Harry Potter." Even Beyoncé had to make hundreds of songs to get 'Halo.'

"When you don't have the freedom to take your idea and turn it into a historic enterprise, we all lose," said Zuckerberg. "Right now our society is way over-indexed on rewarding success and we don't do nearly enough to make it easy for everyone to take lots of shots."

Zuckerberg, who is the world's fifth-richest person, worth $62.3 billion, talked about student loans weighing down a generation. 

"Let's face it: There is something wrong with our system when I can leave [Harvard] and make billions of dollars in 10 years, while millions of students can't afford to pay off their loans, let alone start a business," said Zuckerberg eliciting audience applause.

Zuckerberg, 33, made an urgent appeal to his generation, millennial to millennial:"To keep our society moving forward, we have a generational challenge  —  to not only create new jobs, but create a renewed sense of purpose," Zuckerberg told Harvard graduates. "It's not enough to have purpose yourself. You also have to create a sense of purpose for others."

Near the end of his commencement address, Zuckerberg zeroed in on a subject that is close to his heart: immigration. Zuckerberg's eyes misted and his voice broke as he recalled a conversation he had with a high school senior who he mentors. The young man feared he could not attend college because he was undocumented. Zuckerberg treated him to breakfast on his birthday and asked what he wanted as a gift. The young man responded: "A book on social justice."

"I was blown away. Here's a young man who has every reason to be cynical. I can't even say his name because I don't want to put him at risk of deportation. He didn't know if the country he calls home — the only one he's known — would deny him his dream of going to college. But he wasn't feeling sorry for himself. He wasn't even thinking about himself," Zuckerberg said. "He has a greater sense of purpose and he's going to bring people along with him."

"If a high school senior who doesn't know what the future holds for him can do his part to move the world forward," said Zuckerberg as he held back tears, "we owe it to the world to do our part too.

With his wife, Priscilla, in the audience, he pointed to the dormitory where he launched Facebook, and remarked that meeting her there was the best thing to happen to him at the university.

"I had just launched this prank website Facemash, and the ad board wanted to 'see me.' Everyone thought I was going to get kicked out. My parents came to help me pack. My friends threw me a going away party. As luck would have it, Priscilla was at that party with her friend. We met in line for the bathroom in the Pfoho Belltower, and in what must be one of the all time romantic lines, I said: 'I'm going to get kicked out in three days, so we need to go on a date quickly,'" he told the audience.

"You're getting kicked out soon, too," he reminded the Harvard grads. "Actually, any of you graduating can use that line," he joked.

Zuckererg and Pricilla have been married for five years and have a daughter, Max, and are expecting a second child.

Uttara Choudhury is a writer for Forbes India and The Wire. In 1997, she went on the British Chevening Scholarship to study Journalism in the University of Westminster, in London.

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