• by David Goetzl  @dgoetzl, January 16, 2008

Mark Lazarus, who had a meteoric rise at Turner Broadcasting from account executive to oversight of leading cable networks TBS and TNT, is leaving the company after 18 years.

Turner said the move comes amid a restructuring that provides greater responsibilities for three executives. As president of the entertainment group, Lazarus also oversaw the recently added truTV and the popular Cartoon Network.

Lazarus' departure surely prompted surprise, given his accomplishments during his tenure, including notable growth for Cartoon's Adult Swim block, the securing of several prominent sports-rights agreements and the integration of truTV. He also brought Charles Barkley on board as an NBA commentator, where the entertaining former star is considered a big draw for Turner's NBA coverage.

Turner appears to be splitting Lazarus' duties between the three executives receiving promotions Tuesday. Steve Koonin becomes president of the Turner entertainment networks, with some ad sales oversight; David Levy takes over all Turner sales, including CNN; and Stuart Snyder now serves as president-COO of the animation division led by Cartoon. All three reported to Lazarus.

"For some time now, Mark and I have been talking about the future structure of the company," Turner CEO Phil Kent said in an internal memo. "In the new structure that I have decided upon, there was not a role of scale that Mark was interested in."

Lazarus joined Turner as an account executive in sports in 1990, eventually becoming head of all Turner sports sales. He went on to become president of Turner Sports en route to taking the role of president of the Turner Entertainment Group in 2003--where TNT and TBS battled USA for cable ratings leadership.

"I feel a great sense of pride in what we have accomplished in my 18 years at Turner Broadcasting," Lazarus said in a statement. "Leading and managing a group of people and a portfolio of businesses, we have achieved innovative success in the sports, entertainment and kids arenas for both television and the digital market. Having built long and enduring relationships throughout these industries, I look forward to my next challenge and opportunity."

Under Koonin, TBS and TNT have been re-branded as comedy and drama networks, respectively, while TNT has a breakout hit in "The Closer." Both networks have moved more aggressively into original programming. In addition to TBS and TNT, Koonin oversees all operations of TCM and truTV. As president of Turner Broadcasting sales, Levy takes oversight of all sales activities, including news networks. He also continues as president of Turner Sports.

Snyder oversees not only Cartoon, but the growing Adult Swim night-time block and Boomerang, as well as related digital properties.

Entertainment ad sales executive vice president Linda Yaccarino will report jointly to Koonin and Levy; Beth Goss, executive vice president of Cartoon Network sales, will do the same with Snyder and Levy; and CNN's sales executive Greg D'Alba now reports to Levy.

--Wayne Friedman contributed to this report