NBC chief exec Jeff Zucker today told his employees that he will be leaving the network — not of his own volition — as soon as the company’s pending merger with Comcast is complete, something that is expected to occur right around the end of the year.

Even as he said he accepted the logic of a new owner seeking to install its own chief executive, Mr. Zucker also described his departure as both “incredibly emotional” and “gut-wrenching in the sense that you have spent your whole life here at NBC.”

In the face of persistent rumors that Comcast would seek to remove Mr. Zucker the first chance it got, Mr. Zucker had said in previous interviews that he had in no way foreclosed the possibility of staying on. G.E., which retained 49 percent of the company, had done its part by locking Mr. Zucker into the position, awarding him a new three-year contract seven months ago that was designed to take him into and past the takeover by Comcast.

Aaahhh … Mergers: Always messy, always difficult, always tumultuous.

Especially during the transition period, the uncertainty among employees can have a significant effect of morale, stress and, ultimately, productivity. Even Zucker himself has been unsure of the company’s direction for some time.

“Look, I knew from the day this was announced that this was a possibility,” Mr. Zucker said. “I wasn’t going to shut the door on anything. But in the last nine months it became increasingly clear that they did want to put their own team in place — and I didn’t want to end up being a guest in my own house.”

While he often faced withering criticism in Hollywood circles for his leadership of the entertainment division of the NBC network — in his note to the staff he mentioned the “ups and downs” the company had experienced — Mr. Zucker said he did not detect “any particular reason” beyond the broad desire for new leadership for Comcast’s inclination to make a change.

Change inevitably happens.

And obviously when two companies come together, there is going to be a lot of deliberation and lag time in major announcements. The process of merging is just that — a process. But companies need to know that this uncertainty can lead to a working environment that is less than optimal.

That effects all mergers. But specifically when it comes to media companies, there are a bevy of other risks involved.

In fact, we broke down the NBC/Comcast merger in our May cover story, detailing the liability, intellectual property, data security, privacy and insurance integration issues associated with a media merger.

We also took a look at the epic failure of the AOL/Time Warner merger and Google’s acquisition of YouTube.

Jeff Zucker’s decision to reinstall Jay Leno into The Tonight Show over Conan O’Brien will go down as one of the last stamps he put on the only company he has ever worked for.