Ask Ashton Kutcher: Nothing can be more daunting than coming aboard a proven ratings winner and making sure the series remains on track.

Gary Glasberg stepped in as the showrunner of “NCIS” this season after serving as an exec producer since 2009. It’s an assignment he didn’t take on lightly.

“Was I afraid of steering a successful series off course? Of course.” Glasberg says. “I put that pressure on myself constantly. Don Bellisario gave birth to this thing and Shane Brennan nursed it to where it is today, but I was happy to take over the reins.”

Glasberg has a reputation for being an even-keeled fellow who eased himself into the tight “NCIS” family. He made the commitment to stick to what has worked in the past while driving the series onward with his own stamp.

“Gary got the heartbeat of the show and then gradually allowed his own identity to shine through,” says co-star Rocky Carroll. “There was never a sense that there was a new sheriff in town. He brought himself into the show organically and that was Gary’s strong suit.”

Glasberg had a good run as exec producer on a string of procedurals before coming on board at “NCIS.” He left “The Mentalist” to join “NCIS” after working on other skeins, including “Shark,” “Bones” and “Crossing Jordan.”

But this is the first time he’s been the man in the hot seat. And as the series showrunner, Glasberg engages in complete transparency by emphasizing an open work environment among the cast, crew and writing staff.

“We make sure now that there’s a writer that’s always on set and all of our offices are a stairwell away,” Glasberg says. “The door is always open. We do our best to make sure that everybody feels comfortable with the material and everyone’s ready to go.”

Brennan took over at the beginning of season five (2007) during a tumultuous time in the show’s relatively calm history. He was the replacement for Bellisario, who had a public standoff with series star Mark Harmon.

Brennan joined “NCIS” in 2006 and later created the spinoff “NCIS: Los Angeles.” For the past two years, he’s been running both series while grooming Glasberg to take over “NCIS.”

Brennan says it was very important to find a showrunner successor at “NCIS” who would build upon what he and team had created over the past four years.

“Anointing makes me sound papal and I’m far from that, but I was looking for someone to take over without disruption,” Brennan says. “Nothing upsets Gary. He handles things well and he’s a nice guy to be around. On top of that he’s a bloody good writer.”

‘NCIS’ 200th Episode
Dramatic growth spurt | Showrunner transition goes smoothly | Authenticity matters | Procedural also a cable, worldwide sensation