McLennan will take the newly created position of executive vice president, office of the chairman, and report to Chief Executive Rupert Murdoch and President Chase Carey.
His duties include working with advertisers to develop marketing partnerships with News Corp's brands which include Fox, The Wall Street Journal and The Sun in the UK, among many others.
A good part of McLennan's focus will be on News Corp's fast-growing international markets.
As we grow our international footprint we see a real opportunity to bolster the value of our brand, Murdoch said in a statement.
The Australian-born McLennan stepped down as global chairman and chief executive of Young & Rubicam last May after taking the post 2006.
(Reporting By Yinka Adegoke in New York, editing by Matthew Lewis)