Younger son James, who in 2012 stepped down as head of UK newspaper business News International (NI) in the wake of the phone-hacking scandal, has also been given a bigger role as co-chief operating officer at 21st Century Fox.
Lachlan Murdoch, 42, had previously worked for 13 years as an executive at his father's News Corporation, by 2007 becoming its deputy chief operating officer.
He stepped back from the business to concentrate on his Illyria investment company with interests in Australian TV and radio.
News Corporation was split into the News Corp publishing arm and 21st Century Fox entertainment division last year. Lachlan and James serve as directors of both.
In a statement issued by 21st Century Fox, Rupert Murdoch, 83, said: "Lachlan is a strategic and talented executive with a rich knowledge of our businesses.
"I'm very pleased he is returning to a leadership role at the company, where he will work closely with me."
The company said Lachlan would work closely with senior management and the board to develop global strategies and guide the overall corporate agenda, dividing his time between Sydney and New York.
In a separate News Corp statement, Rupert Murdoch said: "Lachlan will help us lead News Corp forward as we expand our reach and invest in new technologies in markets around the world."
James Murdoch, 41, who has been promoted from deputy chief operating officer at 21st Century Fox, resigned as chairman of BSkyB in 2012, two months after relinquishing his role at NI.
He said at the time he had decided to step down from NI to devote himself to other roles at News Corp - not because he had known about alleged criminal wrongdoing at the News of the World.
His father said today: "James has done an outstanding job driving our global television businesses and our shareholders, customers and colleagues will benefit greatly from his many talents."
Since the closure of the News of the World, NI has been replaced by a new company, News UK, which controls The Sun, The Times and The Sunday Times.
Other News Corp titles include the Wall Street Journal, the New York Post, and Australia's Daily Telegraph.
21st Century Fox includes the Fox TV networks and other international broadcasters as well as film studio Twentieth Century Fox, and also owns a large chunk of BSkyB.