“This kind of decisiveness and moving rapidly, not just at the top but deep into the organization, is unusual in media takeovers,” said Louis Ureneck, chairman of the journalism department at Boston University. “There tends to be some patience about getting to know the operation and making a smooth transition. But he’s operating like a young man who’s bought a sports car and can’t wait to hop in and drive it around.”

None of that should be surprising from Mr. Murdoch, who is known for being sure of what he wants to do with each of his many properties  often molding them to reflect his own views and wasting no time in doing it. His habit of detailed, personal control contrasts starkly with decades of hands-off ownership by the Bancroft family, which viewed almost any involvement as unethical meddling.

The takeover puts vast resources behind a newspaper that is marginally profitable at best, in part because it has defied the industry trends of cutting staff and circulation. The News Corporation has $29 billion in annual revenue compared with $2 billion for Dow Jones, and Mr. Murdoch has shown repeatedly that he is willing to invest in his properties  even to take heavy losses on some of them  in order to win audiences and advertisers away from their competitors.

With a bodyguard and his longtime secretary in tow  as well as the occasional News Corporation executive  Mr. Murdoch has been a frequent presence in Dow Jones offices, meeting with executives, the editorial page editor of The Journal, Paul Gigot and, in the main newsroom two floors below, Marcus W. Brauchli, the managing editor.

In a handful of walks through the newsroom and a visit to The Journal’s printing plant in South Brunswick, N.J., Mr. Murdoch, 76, has revealed little about his intentions, employees say. But they add that at each stop, he has asked questions about their work and displayed an astonishing command of detail about what they do, from production schedules to running the presses.

There are already firm plans to eliminate The Journal’s Marketplace section, containing articles on business trends and technology, in the first half of next year, with a new section taking its place, according to people at Dow Jones and the News Corporation who have been briefed on the changes. The editor of Marketplace, Melinda Beck, recently left that post to write a column on health, and no replacement has been named.

Image Marcus W. Brauchli, the managing editor of The Journal. Credit... Marc Bryan-Brown photography

There are also plans to replace dozens of the newsroom staff, while other personnel changes reflecting Mr. Murdoch’s priorities have already begun, including building up the Washington bureau and shopping for reporters and editors to hire away from The Journal’s competitors.