SAN FRANCISCO - Yahoo! on Tuesday announced that co-founder Jerry Yang has resigned from its Board of Directors and all other positions with the company.

Co-founder and former CEO of Yahoo! Inc. Jerry Yang arrives for the announcement of a commitment pledge at the Clinton Global Initiative in New York in this Sept 22, 2010 file photo. [Photo/Agencies]

Yang has also resigned from the Boards of Yahoo! Japan and Alibaba Group Holding limited, said the company in a press release.

"My time at Yahoo!, from its founding to the present, has encompassed some of the most exciting and rewarding experiences of my life. However, the time has come for me to pursue other interests outside of Yahoo," said Yang in a letter to Yahoo! Board Chairman Roy Bostock.

"As I leave the company I co-founded nearly 17 years ago, I am enthusiastic about the appointment of Scott Thompson as Chief Executive Officer and his ability, along with the entire Yahoo leadership team, to guide Yahoo! into an exciting and successful future," he said.

Yang served as a member of Yahoo's board of directors since he and David Filo co-founded the company in 1995. He served as chief executive officer from June 2007 to January 2009.

Yang's departure came just two weeks after Yahoo! hired former PayPal executive Scott Thomson as its new CEO.

He was reported to be the one who blocked Microsoft's attempt to acquire Yahoo! in 2008 with $47.5 billion. Earlier this month, Yang also reportedly told major private equity firms that he and other board members would not support a takeover offer for the entire company. Some Yahoo! shareholders have been calling for his resignation.