CBS Entertainment Chief Nina Tassler Is Stepping Down

For more than a decade, CBS Entertainment chief Nina Tassler seemed like the last woman standing in network TV, maintaining control of the most-watched broadcast network's drama, comedy and late-night offerings while executives at rival outlets rose and fell.

But today, Tassler announced plans to leave CBS by the end of the year. The statement from CBS says the move was voluntary; Tassler has held the role since 2004 and has long spoken of wanting to explore new avenues in her career. She has a book, What I Told My Daughter, scheduled for publication in April.

It's a surprising development at a network known for executive stability. The change also replaces CBS' top-ranking female executive at a time when she was gaining notoriety for supporting other female executives and producers at the network.

Glen Geller, who worked under Tassler as executive vice president of current programming, has been named president of CBS Entertainment effective immediately. He's expected to work with Tassler as she transitions out of the chairman's job this year.

Tassler signed a three-year contract in 2014 that elevated her to chairman, and she's expected to continue with CBS as an adviser until the deal ends in 2017. She is seen as a close friend and ally of CBS President and CEO Les Moonves — though Moonves, with his reputation for micromanaging and love of the spotlight, could often overshadow his entertainment chairman.

Tassler's statement was full of praise for Moonves and for her team: "I owe a tremendous debt of gratitude to Leslie, my colleagues at CBS and all the actors, producers and writers who were part of this incredible journey. I will always love this place, yet it is time for my next chapter, and I'm thrilled that I can pursue my other creative interests while still being part of the Company."

The change comes at a delicate time for CBS; it just finished revamping its late-night schedule with the launch of Stephen Colbert as host of The Late Show a week ago. Next week, the network will begin to debut its fall lineup of new and returning shows, including a comic book series, Supergirl, which is different from the police procedurals and broad comedies that have proved to be CBS' most successful programs.

Tassler made history in many ways. Besides her long tenure, Tassler is the only woman who leads the entertainment division at any broadcast network by herself. (Dana Walden at the Fox network shares duties with co-chair Gary Newman.)

And she's recognized for pushing a network long seen as a haven for male-centered shows into developing dramas with female stars, such as CSI: Cyber, starring Patricia Arquette; The Good Wife, with Julianna Margulies; Halle Berry's Extant; and Mike & Molly, featuring Melissa McCarthy.

Tassler started at CBS in 1997 as vice president of drama, coming from a similar job at Warner Bros. Television. Before taking the reins as head of entertainment, she helped develop popular CBS franchises CSI and NCIS as executive vice president of drama series development.

But Tassler exits CBS at a time when the network faces more diversity challenges — over the past year, it hired Colbert and James Corden to host its late-night shows, continuing the preponderance of white males in that time slot — and an increasingly multicultural audience seeking shows that reflect the lives they lead.