Olbermann rose to prominence as a "SportsCenter" anchor from 1992-97 before one of several contentious departures that have marked his career.
"Olbermann" will premiere Aug. 26, the network said Wednesday. It will generally air at 11 p.m. ET Monday-Friday on ESPN2, depending on live event coverage on the channel. The show will include commentary, interviews, panel discussions and highlights.
Olbermann said in a statement that "I'm overwhelmed by the chance to begin anew with ESPN."
"I've been gone for 16 years and not one day in that time has passed without someone connecting me to the network," he said. "Our histories are indelibly intertwined and frankly I have long wished that I had the chance to make sure the totality of that story would be a completely positive one. I'm grateful to friends and bosses - old and new - who have permitted that opportunity to come to pass. I'm not going to waste it."
His last two politically oriented jobs ended poorly. Olbermann quit abruptly in January 2011 after eight years as a prime-time host at MSNBC, and his later tenure at Current TV lasted a year before he was taken off the air and responded with a lawsuit, settled out of court.
Olbermann served as co-host of NBC's Sunday night NFL pregame show from 2007-09, reuniting with old "SportsCenter" anchor partner Dan Patrick for the last two seasons. He recently added another sports gig, hosting TBS's Major League Baseball postseason studio show.
His new ESPN program will often air opposite "SportsCenter" on the main ESPN network. The company has found over the years that broadcasting competing programming on its various channels expands its overall audience. And starting next month ESPN will have competition in the 11 p.m. slot from new cable channel Fox Sports 1's nightly highlights and analysis show.
ESPN President John Skipper called Olbermann a "one-of-a-kind personality" in a news release announcing the hire.
"These shows will be appointment viewing for that very reason," Skipper said. "Keith brings a blend of editorial sophistication and unpredictability - you can never be sure what you'll get."