Matt Taibbi, who made a name as a fierce critic of Wall Street at Rolling Stone magazine, has joined First Look Media, the latest big-name journalist to leave an established brand to enter the thriving and well-financed world of news start-ups.

Mr. Taibbi will start his own publication focusing on financial and political corruption, he said in an interview on Wednesday. First Look is financed by the eBay founder Pierre Omidyar, who is worth $8.5 billion, according to Forbes. Mr. Omidyar has pledged $250 million to the project.

“It’s obvious that we’re entering a new phase in the history of journalism,” Mr. Taibbi said. “This is clearly the future, and this was an opportunity for me to be part of helping to found something and create something that might carry us into the next generation.”

The site, as yet unnamed, will open this year. Mr. Taibbi will write for it and take an editorial role, while based in New York. There will be “an emphasis on bringing in talented writers who can have fun with the subject in addition to producing solid investigative journalism,” he said.