Jack Dorsey is following in the footsteps of his Silicon Valley idol -- Steve Jobs.
Named Twitter's interim chief executive officer on Thursday, Mr. Dorsey returns to a job he had until being pushed out in 2008 from the firm he helped create. Similarly, Jobs returned to Apple as interim CEO in 1997 after being forced out in 1985, and guided the company to create the iMac, iPhone and iPad.
Mr. Dorsey, 38, demurred when asked during an interview whether he's interested in becoming Twitter's permanent CEO. "It's really up to the search committee and they're going to look at internal and external candidates," he said.
His return signals that Twitter is looking for a leader who can inspire confidence in the company's product vision, after a slew of leadership changes in the past five years, slower growth than anticipated and advertising efforts that have failed to gain traction.
Mr. Dorsey's passion for Twitter, the social-media company which he helped start in 2006 with Evan Williams and Biz Stone, has been evident. Even while running Square Inc., a digital-payments company he co-founded in 2009, Mr. Dorsey has stayed active as Twitter's chairman, serving as adviser to outgoing CEO Dick Costolo, who took the top post in October 2010. The pair meet over dinners most weeks on Tuesdays at Zuni Café near the company's San Francisco headquarters.
Mr. Dorsey recommended that Twitter acquire Vine, the short-video sharing application, to complement Twitter's 140-character messages and helped oversee product development in 2011-2012 before leaving to focus on Square.
The stock jumped as much as 5.6% to $37.84 in early trading Friday after Twitter announced the leadership changes after the markets close Thursday.
"I have a lot of context for what the company's doing around the product and the service, and I don't anticipate any changes in strategy or direction," Mr. Dorsey said in the interview.
Mr. Dorsey tends to lead in terms of big ideas and grand visions. In operational meetings, he leans toward discussing philosophical positions on a product's purpose, as opposed to going through a checklist of action items.
Mr. Dorsey's emulation of Mr. Jobs was highlighted in the book "Hatching Twitter" by Nick Bilton about the company's beginnings.
"Mr. Dorsey began casting himself in the image of Steve Jobs, calling himself an 'editor,' as Jobs referred to himself, and adopting a singular uniform: a white buttoned-up Dior shirt, blue jeans and a black blazer," Bilton wrote, according to a 2013 excerpt in the New York Times.
Much of the story of Twitter's early days involves conflict among the founders. Mr. Dorsey's relationship with Mr. Williams grew so strained that Mr. Williams pushed him out of the CEO role. Mr. Dorsey kept his chairman title, but it was seen as ceremonial.
'Something to Prove'
"After Mr. Dorsey lost his position as CEO, he felt that he had something to prove," according to a 2013 profile in New Yorker magazine. "As some Silicon Valley skeptics saw it, Mr. Dorsey had lucked into one good idea, programmed some simple code, bumbled along as the company surged to success, then claimed more credit than was his due."
Mr. Dorsey and Jim McKelvey set about to develop a portable credit-card reader. They created Square in 2009 and it quickly grew, with a funding round late last year valuing the company at $6 billion. Square now has more than 1,000 employees, Aaron Zamost, a spokesman for the company, said in an e-mail.
Starbucks invested $25 million in the payments provider in 2012 and began using Square's services in 7,000 of its stores.
Square said in December that one in four active U.S. credit or debit cards paid with Square last year and its businesses get more than 1 billion customer visits.
Future Prospects Despite the fast growth, Square has struggled. Doubts linger about its growth prospects as similar devices flood the market and larger rival PayPal spins off from parent EBay Inc. to become a stand-alone payments company.
"Square is running out of runway which may be part of the reason Mr. Dorsey will have more time to spend at Twitter," Gil Luria, an analyst at Wedbush Securities, said in an e-mail.