Sam Altman's been fired before. The polarizing past of OpenAI's reinstated CEO.

Though a revered tactician and chooser of promising start-ups, Altman had developed a reputation for favoring personal priorities over official duties and for an absenteeism that rankled his peers and some of the start-ups he was supposed to nurture, said two of the people, as well as an additional person, all of whom spoke on the condition of anonymity to candidly describe private deliberations. The largest of those priorities was his intense focus on growing OpenAI, which he saw as his life's mission, one person said.