The suspension started for Saturday night's game against the Braves, and bench coach Trey Hillman will serve as acting manager.
The announcement was made after Saturday's Civil Rights Game luncheon by Joe Garagiola, Major League Baseball's senior vice president of standards and on-field operations. Kemp and Mattingly attended the luncheon.
Mattingly, who also was fined an undisclosed amount, received a letter from Garagiola explaining that the manager is responsible for keeping his player from going after an umpire.
"I just didn't understand why, but today I understand," Mattingly said of the suspension. "It said I have to keep my guys under control before I make my argument."
Mattingly speculated on Friday that he would be suspended two games for an extended argument with plate umpire Angel Campos and the crew after Kemp was ejected by Campos. Mattingly also speculated that Kemp would not be suspended, even though Kemp aggressively charged the umpire from the dugout after his ejection.
Kemp said he had not been notified of a fine, which is expected to exceed the customary $500 fine for an ejection because Kemp argued aggressively.
Mattingly has been ejected an MLB-high six games this year. He was suspended one game last year after Clayton Kershaw was ejected for throwing at D-backs pitcher Ian Kennedy after beanball warnings had been issued.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.