Alemayehou will join the board immediately and Cohn will step down, the company said in a release. Elliott, one of Twitter's top 20 investors, will continue to engage with senior management and the board through an "information sharing and engagement agreement," Twitter said.

Cohn, who runs the $40 billion hedge fund's U.S. activism practice, was appointed to the Twitter board in March 2020, as part of a deal with the social media company to let Chief Executive Jack Dorsey keep his job and allow Elliott to take a board seat.

Cohn joined the board alongside Silicon Valley tech investor Egon Durban, co-chief of private equity company Silver Lake.

Elliott had previously pushed to remove Dorsey after criticizing him for holding the CEO position at both Twitter and mobile payments company Square Inc.

After a long period of languishing performance, in which Dorsey admitted Twitter had been slow to innovate and introduce new features, the platform has more recently made a slew of announcements to attract more users and advertisers.

It has committed to doubling its annual revenue by 2023, and last week introduced its first subscription product, Twitter Blue, which lets users edit tweets and customize their app.

(Reporting by Svea Herbst-Bayliss in Boston and Sheila Dang in Dallas; Editing by Matthew Lewis)

By Svea Herbst-Bayliss and Sheila Dang