Hartel struggled to cope with Ogogo's tempo in the early stages of the first round, with the 23-year-old able to avoid the German's attacks.
However, Hartel improved as the first round continued but Ogogo managed to complete some good combinations to take the opener 5-2.
The bout was fought in a much more expansive manner in the second round, with Hartel eager to reduce the deficit.
Ogogo was equal to his opponent's tactics and a good finish to the round allowed the British fighter to extend his lead to 10-6.
The atmosphere created by the ExCel crowd clearly encouraged Ogogo in the final round as he attacked Hartel in the final minute to record a comfortable victory.