Commissioned in the fighter stream in 1979, Kumar replaced Air Marshal S B Deo, a defence spokesperson said.
He was presented with a ceremonial guard of honour by the air warriors.
Prior to taking over as Air Officer Commanding-in-Chief of Eastern Air Command, Kumar was Senior Air Staff Officer, South Western Air Command.
The Air Marshal held various important field and staff appointments during his distinguished service career spanning over 36 years, the spokesperson said.
His wife Devika also assumed the charge as President, Air Force Wives Welfare Association (Regional) today at an official ceremony here, they added.