Hubbard's appointment comes after chief exec Jack Dorsey confirmed media head Katie Jacobs Stanton, product vice president Kevin Weil and engineering head Alex Roetter were all departing the company. He also said Skip Schipper, the company's head of HR, will be leaving too.
Sources told re/code that chief exec Dorsey emailed the company last night to update them on Hubbard's appointment.
Hubbard joined the company in 2013, joining from Ticketmaster Entertainment where he was chief executive officer.
It has been a challenging few months for Twitter, which saw its share price slump to an all-time low last week having struggled to grow its users or satiate its investors.
This has triggered mounting speculation that the firm will become a takeover target, although last week's rumours of a merger with News Corp were found to be false.