After graduating from Keio University, he joined Mitsubishi Motors in 1959.
On December 25, 1958, when Ninomiya was a Keio University student, he debuted for Japan national team against Hong Kong.
After Japan national team failed to qualify for 1976 Summer Olympics in April 1976, Ninomiya became a manager for Japan national team as Ken Naganuma's successor.
Ninomiya managed at 1978 World Cup qualification and 1978 Asian Games.
In 2015, Ninomiya was selected Japan Football Hall of Fame.