UPDATED: With the CBS-Viacom merger plans abandoned and President and CEO of Viacom International Media Networks Robert Bakish named CEO of Viacom, we have the first major executive shakeup at the underperforming Viacom TV networks. One of the company’s highest-ranked executives, veteran Doug Herzog, president of the Music and Entertainment Group, is leaving, effective Jan. 12. He will not be replaced, with the heads of the networks in Herzog’s group now reporting directly to Bakish. You can read Bakish’s internal memo announcing Herzog’s departure under the post.

Herzog has a decades-long association with Viacom, first as president of MTV Productions in the 1980s and of Comedy Central in the 1990s and more recently as head of the entertainment group since 2004. In the past few years, Herzog added more oversight, including over the MTV Networks, in a string of corporate restructurings at Viacom’s faltering cable networks, and he installed new leadership at virtually all networks under his purview.

After a decade of Herzog rising within the Viacom cable networks hierarchy, Bakish three months ago was named President and Chief Executive Officer of a new TV unit, Viacom Global Entertainment Group that combined the VIMN division, which he ran, with the Herzog’s Music and Entertainment Group, which includes MTV, Comedy Central, VH1, Spike and Logo. Those networks’ toppers, Chris McCarthy — who oversees MTV, VH1 and Logo — Comedy Central’s Kent Alterman and Spike TV’s Kevin Kay, will now report directly to Bakish, who is going for a hands-on approach by eliminating a layer in the reporting structure.

At the time of the reorganization, Bakish stressed in an internal memo that Herzog, as well as Nickelodeon Networks president Cyma Zarghami and BET Network president Debra Lee, were all going to stay put. While Zargami and Lee oversee one major brand each, Herzog was in charge of several — run by a president-level executives — making

During his first tenure with MTV, in which he rose to become President of MTV Prods, Herzog developed and supervised MTV News and popular shows such as The Real World, Unplugged and Road Rules, as well as the network’s signature MTV Movie Awards and MTV Video Music Awards.

He then moved to the position of President of Comedy Central in 1995 where, in addition to spearheading several current signature standouts, he launched cult hits such as Win Ben Stein’s Money, Strangers with Candy and the network’s Roast franchise.

Herzog left for stints as President of Entertainment for Fox Broadcasting Company (1998-2000) and President of USA Network (2001-2004) before rejoining Viacom as president of the entertainment division. His departure was first reported by Reuters.

Here is Bakish’s memo:

Team,

I wanted to share the news that Doug Herzog, President of the Music and Entertainment Group, is leaving Viacom next month.  Below is the note that he sent out today to his teams in the Music and Entertainment Group.  The brands in that Group will report directly to me moving forward.

In all the time I’ve known Doug, he’s never been an easy act to follow.  South Park.  The Daily Show.  The Video Music Awards and MTV News.  Chappelle’s Show and The Colbert Report.  Name some of the most indelible hits in our history, and they’ve probably got Doug’s name in the credits and his creative fingerprints all over them.   In his initial tenure at MTV, he came over from CNN as a fledging producer and rose to become the President of MTV Productions, and an architect of the brand’s leap from music videos to original programming.  He oversaw the launch of “The Real World” and “Road Rules,” as well as the VMAs, “Movie Awards” and “Unplugged.”

That run alone would’ve put Doug in the Hall of Fame, but he followed it up by taking the job as President of Comedy Central in 1995, building that brand from a cult phenomenon to its current iteration as a multiplatform powerhouse, beginning with “The Daily Show with Jon Stewart” and continuing through to today with hits like “Broad City” and “Inside Amy Schumer.”  Following stints at USA and Fox, we lured him back into the fold in 2004 to head up the Entertainment Group and, under his leadership, Comedy Central, Spike and TV Land all have enjoyed creative renaissances, from “Lip Sync Battle” to “Hot in Cleveland” to “Bar Rescue” and “Key & Peele.”

Doug gives a lot of credit below to luck, but let’s be honest – no one is that lucky.   Doug made his own luck by being extremely good.  He’s got sharp creative insight, a great eye for talent, and he inspires loyalty and adoration in his people.  He’s also the funniest guy in pretty much any room and, above all, he’s an incredible human being.

I know this doesn’t need to be said, but I hope you’ll join me in thanking Doug for all of his incredible contributions to our company.

Best,

Bob