Microsoft CEO Steve Ballmer is planning his retirement in the next nine months from the software giant he helped build, but he’s also assisting with a reorganization for his successor. In exclusive interviews with The Wall Street Journal, Ballmer recounts what led to his surprise resignation announcement from Microsoft in August. Microsoft’s board had been rightly pushing Ballmer to go faster. Lead director John Thompson had been pushing Ballmer to move faster as competitors gained ground on key consumers markets like smartphones and tablets.

"Maybe I'm an emblem of an old era, and I have to move on."

"Maybe I'm an emblem of an old era, and I have to move on," Ballmer admits to the WSJ. "As much as I love everything about what I'm doing," he says, "the best way for Microsoft to enter a new era is a new leader who will accelerate change."

While Ballmer is still reorganizing key parts of Microsoft, including a change to the company’s notorious employee-ranking system, he didn’t move quickly as he was focused on shipping Windows 8 at the time. The departure of Windows chief Steven Sinofsky shortly after Windows 8 was released, further complicated matters. Ballmer set about simplifying his management reporting structure, with some resisting the change, but he began to doubt he was the right man to execute his own plan.

"Face it: I'm a pattern."

"At the end of the day, we need to break a pattern ... face it: I'm a pattern," says Ballmer, recounting how, in May, he came to the conclusion Microsoft might be able to change faster without him in charge. Shortly afterwards, the WSJ reports Ballmer started drafting around 40 retirement letters. Ballmer, know for his passion and energy, demonstrated his love of Microsoft and his emotional decision to step down during a farewell speech to employees in September.

While speculation continues over Ballmer’s replacement, he says he’s planning no big decisions for at least six months. He’s open to staying at Microsoft as a director, but he’s also had offers of university teaching and even coaching his son’s high-school basketball team.