Interpublic CEO Michael Roth has picked well-respected Weber Shandwick chief Harris Diamond to run its McCann Worldgroup advertising flagship. The PR world should cheer the fast-talking Brooklyn Law School graduate, who began his career in the Kings County D.A. office.

He’s in a strong position to one day lead one of the world’s biggest ad/PR conglomerates. That would be quite a coup for PR, a validation of its leading role in the communications space.

Diamond told me more than once that cost-effective PR -- not advertising -- should power corporate communications programs during these social media-driven times. He told Ad Age that PR should be the “brand stewards rather than brand tactical executioners.” We’ll see how that philosophy plays out with the ad people of McCann.

The 59-year-old Diamond takes over for Brit Nick Brien, who was the second highest paid executive at IPG during the past year. His base salary was $1.2M, compared to Roth’s $1.4M. Roth did trump Brien in the total compensation column by a $13M to $4.8M margin.

Diamond began his PR career at the legendary Sawyer Miller Group political shop. He moved Sawyer Miller into the corporate world and -- with current Weber Shandwick chairman Jack Leslie, Ed Reilly and Mark Malloch Brown -- bought the shop from David Sawyer in 1988. The partners sold Sawyer Miller to True North, which merged Sawyer Miller with Bozell to create BSMG.

Interpublic completed the True North acquisition in 2001 and Diamond, Leslie and Andy Polansky built Weber Shandwick into one of world’s largest PR firms. Harris has had a heckuva career.

Roth, 66, has helmed IPG since 2005. The former Mony Group CEO has done a good job in getting IPG’s financial house in order. In announcing Diamond’s appointment at McCann, Roth lauded his understanding of the “business needs of global CEOs, across a range of industries.” That expertise is key in today’s linked society.

As chief of IPG’s constituency management group (Weber Shandwick, GolinHarris, Octagon, Jack Morton Worldwide, DeVries PR, FutureBrand and Rogers & Cowan), Diamond was running a large part of IPG.

He may soon run the entire show.