Jose Antonio Vargas, a Pulitzer Prize-winning journalist, is going on network television Thursday to announce he is an illegal immigrant. (Define American/Associated Press)

A journalist who shared a Pulitzer Prize  for his coverage of the Virginia Tech massacre for The Washington Post has admitted he is an illegal immigrant.

Journalist Jose Antonio Vargas, 30, says a fake Oregon driver's licence allowed him to get his first full-time job at a U.S. newspaper.

Vargas worried about the licence expiring, saying he feared being exposed. And despite successfully obtaining a Washington driver's licence — which could have served as an identity card for the next five years — he decided to go public with his immigration status in an effort to push reform of U.S. immigration laws.

"I'm done running. I'm exhausted," Vargas wrote in a New York Times Magazine essay posted online  Wednesday. "I don't want that life anymore."

He also spoke to ABC News in interviews that will air Thursday and Friday.

Vargas, whose mother sent him from the Philippines to live with his grandparents in California when he was 12, said he now wants to push Congress to pass a bill called the DREAM Act and open a path to citizenship for people like him if they go to college or serve in the military.

On Wednesday, Vargas launched a campaign called Define American to use stories of immigrants like him to urge Congress and the Obama administration to pursue immigration reform. His high school principal and superintendent have signed on as board members.

'I just thought to myself, you know, I couldn't give anybody any reason to ever doubt that I'm an American' —Jose Antonio Vargas

"You can call me whatever you want to call me, but I am an American," Vargas told ABC. "No one can take that away from me."

He says he didn't know about his citizenship status until four years after he arrived in the U.S., when he applied for a driver's permit and handed a clerk his green card.

"This is fake," a Department of Motor Vehicles clerk said, according to Vargas' account. "Don't come back here again."

Vargas confronted his grandfather, who acknowledged he purchased the green card and other fake documents.

"I remember the very first instinct was, 'OK, that's it, get rid of the accent,"' Vargas told ABC. "Because I just thought to myself, you know, I couldn't give anybody any reason to ever doubt that I'm an American."

He convinced himself that if he worked hard enough and achieved enough, he would be rewarded with citizenship, Vargas wrote in the magazine piece.

'Marry an American' grandfather advises

When Vargas told his grandfather he was gay, it made life even more difficult. He was kicked out of his house for a few weeks in high school — and his grandfather said Vargas needed to marry an American woman in order to get a green card.

Vargas said he told Mountain View High School Principal Pat Hyland and school district Superintendent Rich Fisher about his problem. They became mentors and surrogate parents, eventually finding a scholarship fund for high-achieving students that allowed him to attend San Francisco State University.

Vargas found internships at The San Francisco Chronicle and the Philadelphia Daily News. He was denied an internship at The Seattle Times because he didn't have all the documents they required. But he kept applying and got an offer from the Washington Post.

The newspaper required a driver's licence, so Vargas said his network of mentors helped him get one from Oregon, which has less stringent requirements than some other states.

Once hired full-time at the Post, he used the fake licence to cover Washington events, including a state dinner at the White House, Vargas recalled.

Avoided covering immigration issues

He wrote that he felt nearly paralyzed with anxiety that his secret would be found out at the Post. He tried to avoid reporting on immigration policy, but at times, it was impossible. At one point, he wrote about then-Sen. Hillary Rodham Clinton's position on driver's licences for illegal immigrants.

Vargas said he eventually told his mentor, Peter Perl, now the newspaper's training director. Perl told him that once he had accomplished more, they would tell senior editors at the Post.

Vargas shared a Pulitzer Prize for the Post's coverage of the Virginia Tech shootings. A 2006 series he wrote on the HIV/AIDS epidemic in Washington inspired a documentary film. But he never did reveal his immigration status to senior editors at the newspaper.

In an article published Wednesday evening on the Post's website, the newspaper reported that Vargas approached his old newspaper in March about writing his story. It was to be published Sunday, but was killed by executive editor Marcus Brauchli several days before its scheduled publication.

Condemned by Washington Post

On Wednesday, Washington Post spokeswoman Kris Coratti condemned the actions of Vargas and Perl in covering up Vargas's immigration status.

"What Jose did was wrong. What Peter did was wrong," Coratti said, declining to comment further on personnel matters. "We are also reviewing our internal procedures, and we believe this was an isolated incident of deception."

Coratti would not say why the Post backed down from publishing Vargas story.

Illegal immigrants in Vargas's situation can't simply apply for citizenship in the U.S. They would have to go back to their countries and start the process from scratch, which could take years, except for rare cases where employers sponsor immigrants or they find other connections.

Last year, Vargas wrote a profile of Facebook CEO Mark Zuckerberg for The New Yorker. Most recently, he was a senior contributing editor at Huffington Post.