The eight-episode first season stars Grammer as Tom Kane, the mayor of Chicago who learns he is suffering from a degenerative brain disorder and only has years to live in the midst of his gubernatorial campaign.
"The first time we read Farhad [Safinia's] script, we knew we had to make Boss," Starz President Chris Albrecht said in a statement. "With each episode, the story grew richer, and the cast continued to turn in breakthrough performances... For our viewers, we felt it important to start working on the next season as soon as possible."
Production on the second season will begin in early 2012. Boss premieres Friday, Oct. 21.