Singleton, 62, co-founded MediaNews in 1984 with Richard B. Scudder, and it grew to become the country's second largest newspaper company as measured by daily circulation.
After MediaNews went through Chapter 11 bankruptcy proceedings, and Alden Global Capital became a major shareholder of the company, Singleton left the position of CEO in January 2011 but remained as chairman and publisher of the Denver newspaper. At the same time, his heir apparent, company president Jody Lodovic, stepped down.
Jon Paton, head of Digital First Media, now oversees MediaNews and the Journal Register chain.
MediaNews Group owns the Bay Area News Group chain of newspapers and websites, which include the Oakland Tribune, Contra Costa Times, Mercury News, Palo Alto Daily News, San Mateo County Times, Marin Independent Journal and other dailies.
Mac Tully, formerly head of the Bay Area News Group, will take over Singleton's job as publisher of the Denver Post.
Singleton said that multiple sclerosis, a condition he was diagnosed with 26 years ago, has slowed him physically.
"Fighting MS has actually caused me to be healthier in some aspects of my life," he said. "But it makes it more difficult to do the things you want to do."
Singleton said he will spend more time with his family and at his Colorado cattle ranches.
(Photo credit: Craig F. Walker, The Denver Post)