Rita Brogley, who was vice president of business development, will take over for Perlman in both positions. Perlman will stay on the company's board of directors as vice chairman and will continue to advise Moxi on future projects.
Moxi Digital is a Palo Alto, Calif.-based start-up formerly known as Rearden Steel Technologies. It designs software and hardware for cable and satellite set-top boxes, turning them into digital entertainment centers for the home.
"The first year of a start-up is really my specialty," Perlman said. "The business and the execution of our plans are where Rita really outshines me."
Perlman will focus his attention on projects at digital media production company Rearden Steel Studios, the content arm of Rearden Steel. He founded Rearden Steel, which also includes affiliates Moxi Digital, Rearden Steel Productions and Rearden Steel Entertainment.
"Steve really laid out the road map for (Moxi Digital)," Brogley said. "Now we need someone to roll up their sleeves and focus on execution." In particular, she said, the company this year will concentrate on set-top box trials with network partners.
Moxi Digital first revealed its plans and products when it debuted with its new name earlier this year at the Consumer Electronics Show.
The company entered what is quickly becoming the latest trend in the technology industry: networked home-entertainment products and services, which are aimed at centralizing digital media in one product in the home. Microsoft, Intel, Apple Computer and other major PC companies are developing similar products.
Perlman, as a co-founder of WebTV, was one of the early players in this market. He later sold WebTV to Microsoft in 1997 for what at the time was estimated to be $425 million. WebTV is now part of Microsoft's online unit MSN.
Initially successful, subscriptions to the WebTV service--which helps viewers access the Internet on a TV--are now stalled at around one million.
After the sale of WebTV, Perlman joined Microsoft. He left in 1999 to found Rearden Steel.
Moxi is a privately funded company that received $67 million in its first round of funding from the likes of America Online, Cisco Systems, EchoStar Communications, Mayfield, Vulcan Ventures, The Barksdale Group, The Washington Post Company and Macromedia Ventures.
"The best thing for Moxi would be to appoint a solid CEO to run the day-to-day operations," Liberate Technologies CEO Mitchell Kertzman told CNET News.com following the launch of Moxi Digital. "Steve is more of a visionary and his track record for running operations isn't great."