Mark Greenberg is stepping down as president-CEO of Epix after nearly 10 years at the helm of the premium TV venture he founded with MGM, Lionsgate, and Paramount Pictures in 2008, Variety has learned exclusively.

The shuffle comes five months after MGM completed its $1 billion buyout of the premium cable and digital service. Greenberg said he made the decision to move on after the integration with MGM was complete, even though he signed a new contract last November as Epix went on the block.

“We were committed to completing the integration effectively and efficiently,” Greenberg told Variety. “Having completed the integration effectively and efficiently, it really created a segue for me to  say that it’s time for me to tap into my entrepreneurial spirit. I’ve left this company in good hands.”

Monty Sarhan, Epix’s executive VP of programming, strategy and enterprises will oversee the service in the interim while a new management structure is put in place. Sarhan will report to MGM chairman-CEO Gary Barber. Chris Ottinger, MGM’s president of worldwide TV distribution and acquisitions, and MGM CFO Ken Kay will work closely with Sarhan.

Greenberg, a pay TV vet who previously worked for HBO and Showtime, was the driving force behind the creation of Epix in 2008 as a joint venture of MGM, Paramount Pictures, and Lionsgate. The three studios had been under output deals for theatrical titles with Showtime, but when Showtime decided to cut its spending on theatricals in order to focus on original series, Greenberg rallied the studios to launch their own pay TV service.

“Mark’s been an unbelievable steward of this company,” Barber told Variety. “He’s a complete pro and a great individual. I wish him nothing but the best.”

With Epix’s increasing focus on original programming, it is no surprise that MGM would make management changes as it looks to build Epix as a platform for launching shows that can be sold around the world. “We are significantly increasing our investment in original programming,” Barber said. At the same time, Barber sees opportunity to grow the reach of Epix as a linear and digital distribution platform.

“I think Epix has broad prospects across the globe,” he said.

Barber said there will be some integration of Epix and the MGM Television and Digital unit back-office operations, but oversight of the service will not fall under the purview of division head Mark Burnett.

“Epix will have its own voice. There is a very talented management team there already in place,” he said. “Original programming has only been a focus for Epix in the last year and a half of so. To be a must-have network and increase our subscribers, we need to invest heavily in original content.”

Epix, which formally launched in October 2009, was designed from the start to be a multiplatform service that blended linear and VOD distribution, even as streaming was still in its infancy. Greenberg had some insight into the market from his work as a consultant to Blockbuster Video after he left Showtime in 2006.

Greenberg drew on his cable industry connections to get Epix up and running as a linear channel, but that distribution hit a wall with DirecTV, Comcast and the former Time Warner Cable. The largest MVPDs balked at adding another pay TV channel. The situation drove Epix to cut a movie output licensing deal with Netflix in 2010. That deal, which ended in 2015, helped drive subscribers to Netflix’s then-fledgling streaming service.

The company turned a profit after a year, and last year delivered about $100 million in operating cash income. The channel has fielded documentary series, concert and comedy specials from its inception, but only in the past two years has it moved into scripted series with the spy drama “Berlin Station” and comedies “Graves” and “Get Shorty.” More series are on the way.

During the past year, circumstances aligned to motivate Paramount parent Viacom and Lionsgate to sell their interests to MGM. Viacom had the largest stake with 49% but was in need of cash to help pay down its debt load. Lionsgate, meanwhile, bought Epix rival Starz for $4 billion in 2016, which made its partial stake in Epix less of an important asset to that studio.

Greenberg said he was most gratified to have defied the naysayers who questioned whether Epix would ever get off the ground, let alone turn a profit for its partners.

“We built value for our partners and a great consumer experience,” Greenberg said. “I’m glad that Gary’s the one to take this forward to the next chapter.”