After graduating from Shudo High School, he joined his local club Toyo Industries in 1950.
On October 9, 1955, Shimomura debuted for Japan national team against Burma.
But did not compete, as he was the team's reserve goalkeeper behind Yoshio Furukawa.
He led the club through their first golden era as five-time champions of the league (1965, 1966, 1967, 1968 and 1970).
In 1979, he was named manager for the Japan national team as successor to Hiroshi Ninomiya.