White House press secretary Jay Carney told reporters to take William Daley's decision to resign "at face value" despite news reports that suggest that the departing chief of staff felt marginalized in recent months.
Daley, who is leaving the White House at the end of the month, said he wanted to spend more time with his family in Chicago.
"These jobs are tough," Carney said, comparing time at the White House to dog years.
The White House spokesman said the incoming chief of staff, Jack LewJack LewOne year later, the Iran nuclear deal is a success by any measure Chinese President Xi says a trade war hurts the US and China Overnight Finance: Price puts stock trading law in spotlight | Lingering questions on Trump biz plan | Sanders, Education pick tangle over college costs MORE, is someone who has had relationships with both Democrats and Republicans for decades.
Lew is a "total straight shooter," Carney said, adding that he has "a lot of respect in the business community.
"There is continuity in that respect," he said.
Carney also said Daley would have a "high-profile role" in the reelection campaign.
Asked how responsibilities will be divided up, the spokesman responded: "We will wait until Jack takes over as chief of staff. ... He will make some decisions about how his office is structured."
Carney disputed theories that Daley's departure comes at a rather inopportune time for the president politically, at the start of the reelection year.
"I would disagree with that description," he said. "Bill's leadership has been exceptional. Jack's been there ... every morning. He will slide pretty effortlessly and seamlessly into that role."
Carney said Daley "made up his mind" and "believed it was the right time" to leave the White House. But Carney stopped shy of saying if Obama attempted to persuade Daley to stay through the year.
"I think we've established that the president was surprised but understood Bill's decision," he said. "Bill had made his decision and the president respected that."
This story was updated at 1:11 p.m.