The fabulous life of Jack Dorsey, Twitter's billionaire CEO

Mike Nudelman/Business Insider

Jack Dorsey, CEO of Square and interim CEO of Twitter.

Dorsey was named interim CEO after Dick Costolo stepped down from his post in July. According to Twitter's SEC filing, the board made the decision to keep Dorsey as CEO permanently on Wednesday.

This isn't the first time Dorsey has led Twitter. He cofounded Twitter with Biz Stone and Evan Williams back in 2006, but left the company after he was ousted as CEO in 2008. He returned in 2010 to lead product, but ended up scaling back his responsibilities.

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He will stay on as CEO of Square, the mobile payments company he founded in 2010, while managing new responsibilities at Twitter. 

Dorsey first become a billionaire in 2012 and is now worth an estimated $2.2 billion.

Rebecca Borison wrote an earlier version of this story.