Embattled Twitter CEO Dick Costolo will step down on July 1 and be replaced temporarily by founder Jack Dorsey, the company announced on Thursday.
Costolo will continue to serve on Twitter's board of directors. Dorsey will be interim CEO until a replacement is found, and will also continue his role as CEO of Square, the mobile-payments company he founded. Dorsey previously served as Twitter CEO from May 2007 to October 2008.
"I am tremendously proud of the Twitter team and all that the team has accomplished together during my six years with the company," Costolo said in a statement. "We have great leaders who work well together and a clear strategy that informs our objectives and priorities."
Costolo was co-founder and CEO of FeedBurner, a digital content syndication platform that was acquired by Google in 2007, prior to joining Twitter in 2009 as chief operating officer. He became CEO the following year.
In an afternoon conference call, Costolo said the decision to step down as CEO was his. He said he began talking with board members last year about a succession plan, and with a strong team in place both parties ultimately agreed "now is the right time."
RELATED: POTUS is now on Twitter
"This transition is not the result of anything more than Dick deciding to move on from his role as CEO," Dorsey said.
Costolo's tenure has been rocky, with Wall Street investors and others disappointed at the company's lagging share price, lackluster user growth and fuzzy map toward profitability. Last week, Chris Sacca, an early investor in the company, penned an 8,500-word blog post summarizing what he said was wrong with Twitter and how it could be fixed.
"I do not foresee any changes in strategy or direction," Dorsey said during the conference call. "I believe in the course that the company is on."
Dorsey also said there was no timetable for naming a new CEO.
The search for the new CEO will be led by Peter Currie, the board's lead independent director.
"The board is fully committed to running a thorough process to identify the right CEO to lead Twitter into its next phase of growth," Currie said in a statement. "In the meantime, we are fortunate to have Jack — one of our founders — step back into a management role and help lead Twitter as we continue executing on our strategic priorities."
This story originally appeared on NBCNews.com.