Christina Miller. Christina Miller.

In an unexpected announcement, Christina Miller announced today that is stepping down as president of Cartoon Network, Adult Swim, and Boomerang. She had been in the role for five years.

Here is what we know about the situation:

  • Miller had served as president of Cartoon Network, Adult Swim, and Boomerang since 2014, when she replaced Stu Snyder. Prior to her role at Cartoon Network, Miller worked for sister company Turner Sports, where she oversaw NBA Digital’s portfolio. She first joined Turner (Warnermedia) in 2005 as senior v-p of Cartoon Network Enterprises, overseeing the network’s consumer products and home video businesses.
  • “This is not a decision I came to lightly,” said Miller. “It’s one of the hardest I’ve had to make in my career.” The full text of an internal letter that Miller sent to Cartoon Network employees today can be read below.
  • Earlier this year, it was reported that Miller was under consideration for a more prominent kids and family role at Warner Bros. as AT&T aimed to integrate Cartoon Network more closely with Warner Bros. Animation. Sources told Deadline today that, “Miller was asked to stay on by the new Warnermedia leadership but opted to leave.”
  • Michael Ouweleen.
    Michael Ouweleen.
  • Twenty-three year Cartoon Network veteran Michael Ouweleen will serve as interim president of cartoon Network. Miller will stay on through the end of this year, and will work with Ouweleen on transition strategy.
  • Miller joins a long line of high-profile Warnermedia execs who have exited the company in the past couple years as AT&T resets its cable brands for the streaming age. Other executives who have left include HBO head Richard Plepler, Turner CEO John Martin, Turner president David Levy, Warnermedia ad sales president Donna Speciale, Warnermedia chief of marketing and brand strategy Molly Battin, and Warner Bros. CEO Kevin Tsujihara.

Miller’s letter to CN employees is below:

I wanted to share with you some personal news. After much consideration and thought, I have made the difficult decision to leave the company at the end of the year. This is not a decision I came to lightly; it’s one of the hardest I’ve had to make in my career. Ultimately, it feels like the right time for me to leave and take a little time to think about what comes next, but I do so, feeling immensely proud of the work we’ve done together and so grateful for the experience.

More than 14 years ago, what brought me to this company was the prospect of working on some of the world’s most iconic brands – but what has kept me here all these years are the amazing, talented and all-around great people with whom I’ve had the pleasure of working. The laughing, grinding and executing of big ideas across all of our businesses has been what has set us apart, and the talent contained within the organization is truly awe-inspiring. Every single day, I have been motivated, challenged, educated, entertained and fulfilled by each of you, and my path has been made better and the successes richer because they were achieved together.

What stands out to me most about this experience is the countless opportunities I’ve been afforded, the support of what, at the time, seemed like crazy ideas that ultimately transformed our business, and the trust that was given to me every step of the way. I am grateful beyond measure to the entire executive leadership team past and present for investing in me and allowing me to manage my career path in ways I could have never expected. It has been the experience of a lifetime, and one I will never forget. I leave here considering myself incredibly lucky to have called this “work” for so long.

This is an exciting time for WarnerMedia and it is the start of a new chapter for the company. You all have waited incredibly patiently to begin that next phase and that time is coming. Though I’m not leaving just yet – I’ll be working alongside the interim leadership through the end of the year – when I do, I will not only be watching from afar, but also rooting for you from whichever seat I’m in.

So, this isn’t really goodbye; consider it instead my heartfelt thanks for the experience, and a toast to what’s to come for us all.