Avast! Starboard Value has stormed Yahoo's board of directors. Its CEO Jeff Smith, who has been one of Yahoo’s loudest critics for years, was named to the company's board of directors Wednesday morning. Smith will also be part of Yahoo's Strategic Review Committee, the small group that will weigh the acquisition offers Yahoo's fielded for its core business. 

The move comes after months of Smith pounding the table and demanding that Yahoo CEO Marissa Mayer sell off its core business, which he has described as worthless. Smith, whose firm owns less than 1 percent of Yahoo, was one of the first prominent shareholders to suggest that the company spin off its search, media and advertising businesses from its large stake in Alibaba, claiming the growing value of the latter was hindering the ability of the former to get its house in order. 

Earlier this year, Smith vowed to lead a battle to oust the entirety of Yahoo’s board and replace it with people who would do a better job of guiding the company toward a sale.

"I am pleased that we were able to reach a constructive agreement," Smith said in a statement Wednesday. "We look forward to getting started right away and working closely with management and our fellow board members with the common goal of maximizing value for all shareholders." 

In addition to Smith, Yahoo named three other new board appointees. They are Richard S. Hill, a veteran technology and defense executive who most recently served as the CEO of Tessera Technologies Inc.; Tor R. Braham, the longtime head of technology mergers and acquisitions at Warburg Dillion Read, a subsidiary of UBS; and Eddy W. Hartenstein, a former CEO of the Tribune Co. and DirecTV. 

Two current Yahoo board members, Lee Scott and Sue James, will not to stand for re-election at Yahoo's forthcoming annual shareholder meeting.

Since the news first broke, Yahoo’s stock has dipped 30 cents to $36.82 on the Nasdaq.