BOSTON — As governor of Massachusetts, Mitt Romney could not resist burrowing into the bureaucratic weeds: He once took the statewide math and reading test for 10th graders, then startled his education commissioner by calling to say, “I like No. 14” and rattling off the answer.

As head of the private equity firm Bain Capital, he was so uncomfortable cutting loose struggling employees that a legend grew: executives sent in to his office to be fired emerged thinking they had been promoted.

And as a candidate for president this year, he resisted pressure from advisers to select a running mate before leaving on a high-profile trip overseas, insisting that he makes better decisions with time and reflection.

Mr. Romney’s bid for the White House largely hinges on his own narrowly drawn image of himself as a chief executive: the data-splicing, cost-cutting turnaround expert. But dozens of interviews with those who have worked for him over the past 30 years — in the Mormon Church, business, the Olympics and state government — offer a far more textured portrait of the management style that he might bring to the presidency.