Mosko, who spent two decades building Sony's television business, is stepping down and transitioning to a consulting role with the Culver City studio, the company confirmed Thursday.
Leadership of Sony Pictures Television – part of Tokyo-based Sony Corp. – will be shared by multiple executives who will report directly to Sony Entertainment Chief Executive Michael Lynton.
Duties will be split among programming and production presidents Zack Van Amburg and Jamie Erlicht, worldwide networks head Andy Kaplan, distribution chief Keith Le Goy, and president of advertiser sales and research Amy Carney.
The company said the new reporting structure will help streamline management within the TV unit and more closely integrate the division into the broader Sony Entertainment business.
Mosko's resignation took Hollywood aback when the news broke Wednesday, coming just nine months after he was promoted to chairman of Sony Pictures Television after serving for years as president.
Lynton and Mosko were in the midst of negotiating a new agreement to replace the TV chief's employment contract that was due to expire this fall.
Sony's success in the TV business – with shows such as "Breaking Bad" on AMC and "The Blacklist" on NBC – stands in contrast to its feature film division, which has lagged behind rivals.
The TV studio produces such syndicated juggernauts as "Jeopardy" and "Wheel of Fortune," as well as such prime-time hits as "The Goldbergs" and "Shark Tank" for ABC, "Outlander" for Starz, and "Masters of Sex" for Showtime.
"Steve has overseen some of SPT's greatest triumphs and I wish him the very best in the next chapter of his career," Lynton said in a statement.