The appointment will take effect on Jan. 25, when Selig officially retires.
"I greatly appreciate the opportunity to stay connected to the game in this new capacity," Selig said in a statement. "I will be proud to stand behind Rob's vision for the future and to assist in any ways that he asks. Baseball is the greatest game in the world, and I look forward to seeing our sport flourish under Rob's leadership."
Said Manfred: "Commissioner Selig has had an unparalleled career of decorated service to the National Pastime, and this role will allow the game to benefit from his unmatched institutional knowledge, experience and relationships. I could not ask for a finer mentor during this transition process, and I am grateful that Commissioner Selig will continue to be available to me as a resource."
Under Selig, who has led the industry since becoming Chairman of MLB's Executive Council on Sept. 9, 1992, baseball has experienced record attendance and revenues. Under his leadership, the sport has experienced unprecedented labor peace while adding innovations such as expanded replay, postseason Wild Cards and the birth of Major League Baseball Advanced Media.
Selig was officially elected as baseball's ninth Commissioner on July 9, 1998. After Selig announced his intention to retire on Sept. 16, 2013, Manfred was unanimously elected as Selig's successor at the Owners Meetings in Baltimore on Aug. 14.
Paul Hagen is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.