NBC Universal CEO Jeff Zucker announced plans on Friday to resign after Comcast (NASDAQ:CMCSA) assumes control of the media company.

Zucker, a 24-year veteran of NBCU, had been expected to step down from the position he has held since February 2007. He leaves with a mixed record as the unit’s cable and entertainment properties like USA and Universal Studios have had some pockets of success, but ratings at the NBC broadcast network have sagged, especially in prime-time. 

Comcast is waiting for regulatory approval of a deal it reached earlier this year with General Electric (NYSE:GE) to give the cable giant majority control of a joint venture housing NBCU. Regulators are expected to approve the deal by the end of the year.

“Well, the time has come,” Zucker said in a memo to staff. “Now, it is clear to me that this is the right decision for me and for the company. Comcast will be a great new steward, just as GE has been, and they deserve the chance to implement their own vision. I am proud that they will inherit a company in very good shape, with almost every one of our divisions enjoying their best year ever.”

Zucker was criticized for the failed experiment of moving comedian Jay Leno from the "The Tonight Show" and for the way he handled Leno's replacement, Conan O'Brien, once it became apparent the experiment was not working. 

It’s not clear who will take Zucker’s place, but the New York Post reported earlier this month Comcast could tap former Showtime boss Robert Greenblatt. Other executives mentioned as possible replacements are Ted Harbert, who runs Comcast’s cable entertainment business that includes E! Entertainment, and Stephen Burke, the chief operating officer at Comcast.

Zucker said he doesn’t know what his future plans are, saying he “hasn’t even begun to think about the next chapter.”

Zucker’s departure was announced just hours after CNN President Jon Klein resigned effectively immediately as the network continues to struggle in prime-time. Klein will be replaced by Ken Jautz, who heads HLN.

Time Warner’s (NYSE:TWX) CNN and NBC both compete with FOX News and other networks owned by FOX Business parent News Corp. (NASDAQ:NWSA).

Shares of Comcast were up 3.12% to $18.49 on Friday. GE’s stock was up 1.7% to $16.42.